# XML Component

The XML component can be used to both parse and create XML documents.

## Syntax

```text
nsoftware.PDFSDK.XML
```

## Remarks

The XML component can operate as either a parser or writer of XML.

### Parsing XML

The XML component parses XML documents and verifies that they are well formed. The results are provided through a set of events complying with the SAX2 specification.

In addition, the document structure may be queried through an [XPath](#xpath-property-xml-component) mechanism that supports a subset of the XPath specification.

The parser is optimized for read applications, with a very fast engine that builds internal Document Object Model (DOM) structures with close to zero heap allocations. Additionally, [BuildDOM](#builddom-property-xml-component) can be set to *false*, which reduces the overhead of creating the DOM and offers a fast, forward-only parsing implementation that fires events to provide the parsed data.

When parsing a document, events will fire to provide information about the parsed data. After [Parse](#parse-method-xml-component) returns, the document may be navigated by setting [XPath](#xpath-property-xml-component) if [BuildDOM](#builddom-property-xml-component) is *true* (default). If [BuildDOM](#builddom-property-xml-component) is *false*, parsed data are accessible only through the events.

Events are fired only when qualifying conditions (e.g., the beginning of a new element) are met. In the meantime, text will be buffered internally. The following events will fire during parsing:

- [Characters](#characters-event-xml-component)
- [Comment](#comment-event-xml-component)
- [EndElement](#endelement-event-xml-component)
- [EndPrefixMapping](#endprefixmapping-event-xml-component)
- [EvalEntity](#evalentity-event-xml-component)
- [IgnorableWhitespace](#ignorablewhitespace-event-xml-component)
- [Meta](#meta-event-xml-component)
- [PI](#pi-event-xml-component)
- [SpecialSection](#specialsection-event-xml-component)
- [StartElement](#startelement-event-xml-component)
- [StartPrefixMapping](#startprefixmapping-event-xml-component)

If [BuildDOM](#builddom-property-xml-component) is *true* (default), [XPath](#xpath-property-xml-component) may be set after this method returns. [XPath](#xpath-property-xml-component) implements a subset of the XML XPath specification, allowing you to point to specific elements in the XML document.

The path is a series of one or more element accessors separated by */*. The path can be absolute (starting with */*) or relative to the current [XPath](#xpath-property-xml-component) location.

 The following are possible values for an element accessor:

|  |  |
| --- | --- |
| 'name' | A particular element name |
| name[i] | The i-th subelement of the current element with the given name |
| [i] | The i-th subelement of the current element |
| [last()] | The last subelement of the current element |
| [last()-i] | The subelement located at the last location minus i in the current element |
| name[@attrname="attrvalue"] | The subelement containing a particular value for a given attribute (supports single AND double quotes) |
| .. | The parent of the current element |

 When [XPath](#xpath-property-xml-component) is set to a valid path, [XElement](#xelement-property-xml-component) points to the name of the element, with [XParent](#xparent-property-xml-component), [XNamespace](#xnamespace-property-xml-component), [XPrefix](#xprefix-property-xml-component), [XChildren](#xchildren-property-xml-component) , and [XText](#xtext-property-xml-component) providing other properties of the element. The attributes of the current element are provided in the [XAttributes](#xattributes-property-xml-component) collection.

[BuildDOM](#builddom-property-xml-component) must be set to *true* before parsing the document for the [XPath](#xpath-property-xml-component) functionality to be available.

**Example. Setting XPath:**

|  |  |
| --- | --- |
| Document root | XML.XPath = "/" |
| Specific Element | XML.XPath = "/root/SubElement1/SubElement2/" |
| i-th Child | XML.XPath = "/root/SubElement1[i]" |

**Input Properties**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

- [SetInputStream](#setinputstream-method-xml-component)
- [InputFile](#inputfile-property-xml-component)
- [InputData](#inputdata-property-xml-component)

 When a valid source is found, the search stops.

If parsing multiple documents, call [Reset](#reset-method-xml-component) between documents to reset the parser.

An additional "relaxed" mode allows for lexical parsing of non-XML documents (e.g., HTML). This is enabled by setting [Validate](#validate-property-xml-component) to *false*. In this case, events will be fired as elements, entities, and so on are encountered, but the structure of the document will not be checked for "well-formedness", and the internal DOM structure will not be built.

### Writing XML

To use the component, first decide whether or not to write to a file, a stream, or [OutputData](#outputdata-property-xml-component).

**Output Properties**

The component will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

- [SetOutputStream](#setoutputstream-method-xml-component)
- [OutputFile](#outputfile-property-xml-component)
- [OutputData](#outputdata-property-xml-component): The output data are written to this property if no other destination is specified.

To begin writing the XML document, first optionally set [XMLDeclaration](#xmldeclaration-property-xml-component). If this is not set, the component will use a default XML declaration at the beginning of the document.

Next, begin adding elements to your document. Calling [StartElement](#startelement-method-xml-component) will open an element with the specified name. To create a nested structure, continue calling [StartElement](#startelement-method-xml-component) to open more child elements. To write a value within an element, call [PutString](#putstring-method-xml-component). To close the element that was last opened, call [EndElement](#endelement-method-xml-component). Each time [EndElement](#endelement-method-xml-component) is called, the element at the current level is closed. Alternatively, calling [PutElement](#putelement-method-xml-component) will write the element with the value specified and will also close the element.

To write an attribute of the current element, call [PutAttr](#putattr-method-xml-component) after calling [StartElement](#startelement-method-xml-component). Call [PutAttr](#putattr-method-xml-component) multiple times to add multiple attributes.

Writing comments or CDATA can be done at any time with the [PutComment](#putcomment-method-xml-component) and [PutCData](#putcdata-method-xml-component) methods.

To close your XML document, call [Save](#save-method-xml-component). You can call [Save](#save-method-xml-component) from any location, and it will close any remaining open elements automatically.

## Property List

*The following is the full list of the properties of the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [BuildDOM](#builddom-property-xml-component) | When set to true, this property creates an internal object model of the XML document. |
| [InputData](#inputdata-property-xml-component) | This property specifies the XML data to parse. |
| [InputFile](#inputfile-property-xml-component) | This property specifies the file to process. |
| [Namespaces](#namespaces-property-xml-component) | This property includes a collection of namespaces in the current namespace stack. |
| [OutputData](#outputdata-property-xml-component) | The output XML after processing. |
| [OutputFile](#outputfile-property-xml-component) | This property includes the path to a local file where the output will be written. |
| [Overwrite](#overwrite-property-xml-component) | This property indicates whether or not the component should overwrite files. |
| [Validate](#validate-property-xml-component) | This property controls whether documents are validated during parsing. |
| [XAttributes](#xattributes-property-xml-component) | This property includes a collection of attributes of the current element. |
| [XChildren](#xchildren-property-xml-component) | This property includes a collection of child elements of the currently selected XML element. |
| [XComments](#xcomments-property-xml-component) | This property includes a collection of comments of the current element. |
| [XElement](#xelement-property-xml-component) | This property includes the name of the current element. |
| [XMLDeclaration](#xmldeclaration-property-xml-component) | This property specifies details of the XML declaration. |
| [XNamespace](#xnamespace-property-xml-component) | This property includes the namespace of the current element. |
| [XParent](#xparent-property-xml-component) | This property includes the parent of the current element. |
| [XPath](#xpath-property-xml-component) | This property provides a way to point to a specific element in the document. |
| [XPrefix](#xprefix-property-xml-component) | This property includes the prefix of the current element. |
| [XSubTree](#xsubtree-property-xml-component) | This property includes a snapshot of the current element in the document. |
| [XText](#xtext-property-xml-component) | This property includes the text of the current element. |

## Method List

*The following is the full list of the methods of the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Config](#config-method-xml-component) | Sets or retrieves a configuration setting. |
| [EndElement](#endelement-method-xml-component) | This method writes the closing tag of an open XML element. |
| [Flush](#flush-method-xml-component) | This method flushes the parser and checks its end state. |
| [GetAttr](#getattr-method-xml-component) | This method returns the value of the specified attribute. |
| [HasXPath](#hasxpath-method-xml-component) | This method determines whether a specific element exists in the document. |
| [InsertAttr](#insertattr-method-xml-component) | This method inserts a new attribute into the current element. |
| [InsertElement](#insertelement-method-xml-component) | This method inserts a new child element into the current element. |
| [Interrupt](#interrupt-method-xml-component) | This method interrupts the current method. |
| [LoadDOM](#loaddom-method-xml-component) | This method loads the document object model (DOM) from a file. |
| [LoadSchema](#loadschema-method-xml-component) | This method loads the XML schema. |
| [Parse](#parse-method-xml-component) | This method parses the specified XML data. |
| [PutAttr](#putattr-method-xml-component) | This method writes an XML attribute. |
| [PutCData](#putcdata-method-xml-component) | This method writes an XML CDATA block. |
| [PutComment](#putcomment-method-xml-component) | This method writes an XML comment block. |
| [PutElement](#putelement-method-xml-component) | This method writes a simple XML element with a value. |
| [PutRaw](#putraw-method-xml-component) | This method writes a raw XML fragment. |
| [PutString](#putstring-method-xml-component) | This method writes text inside an XML element. |
| [RemoveAttr](#removeattr-method-xml-component) | This method removes an attribute from the current element. |
| [RemoveChildren](#removechildren-method-xml-component) | This method removes the children of the element at the specified XPath. |
| [RemoveElement](#removeelement-method-xml-component) | This method removes the element at the specified XPath. |
| [Reset](#reset-method-xml-component) | This method resets the parser. |
| [Save](#save-method-xml-component) | This method saves the current XML output. |
| [SaveDOM](#savedom-method-xml-component) | This method saves the DOM to a file. |
| [SetAttr](#setattr-method-xml-component) | This method sets the value of an existing attribute in the current element. |
| [SetInputStream](#setinputstream-method-xml-component) | This method sets the stream from which the component will read data to parse. |
| [SetOutputStream](#setoutputstream-method-xml-component) | This method sets the stream to which the component will write the XML. |
| [StartElement](#startelement-method-xml-component) | This method writes the opening tag of an XML element. |
| [TryXPath](#tryxpath-method-xml-component) | This method navigates to the specified XPath if it exists. |

## Event List

*The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Characters](#characters-event-xml-component) | This event is fired for plaintext segments of the input stream. |
| [Comment](#comment-event-xml-component) | This event is fired when a comment section is encountered. |
| [EndElement](#endelement-event-xml-component) | This event is fired when an end-element tag is encountered. |
| [EndPrefixMapping](#endprefixmapping-event-xml-component) | This event is fired when leaving the scope of a namespace declaration. |
| [Error](#error-event-xml-component) | Fired when information is available about errors during data delivery. |
| [EvalEntity](#evalentity-event-xml-component) | This event is fired every time an entity needs to be evaluated. |
| [IgnorableWhitespace](#ignorablewhitespace-event-xml-component) | This event is fired when a section of ignorable whitespace is encountered. |
| [Meta](#meta-event-xml-component) | This event fires when a meta section is encountered. |
| [PI](#pi-event-xml-component) | This event is fired when a processing instruction section is encountered. |
| [SpecialSection](#specialsection-event-xml-component) | This event is fired when a special section is encountered. |
| [StartElement](#startelement-event-xml-component) | This event is fired when a begin-element tag is encountered in the document. |
| [StartPrefixMapping](#startprefixmapping-event-xml-component) | This event is fired when entering the scope of a namespace declaration. |
| [XML](#xml-event-xml-component) | This event is fired as XML is written. |

## Config Settings

*The following is a list of config settings for the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [CacheContent](#CacheContent) | If true, the original XML is saved in a buffer. |
| [Charset](#Charset) | Specifies the charset used when encoding data. |
| [CloseInputStreamAfterProcess](#CloseInputStreamAfterProcess) | Determines whether or not the input stream is closed after processing. |
| [CloseOutputStreamAfterProcess](#CloseOutputStreamAfterProcess) | Determines whether or not the output stream is closed after processing. |
| [EOL](#EOL) | The characters to use for separating lines. |
| [ErrorOnEmptyAttr](#ErrorOnEmptyAttr) | If true, passing an invalid attribute to the GetAttr method will throw an exception. |
| [ExtraNameChars](#ExtraNameChars) | Extra characters for the parser to consider as name characters. |
| [ExtraSpaceChars](#ExtraSpaceChars) | Extra characters for the parser to consider as whitespace. |
| [FlushOnEOL](#FlushOnEOL) | If set, the parser flushes its text buffer after every line of text. |
| [IgnoreBadAttributePrefixes](#IgnoreBadAttributePrefixes) | If true, bad (unknown) attribute prefixes are ignored. |
| [IgnoreBadElementPrefixes](#IgnoreBadElementPrefixes) | If true, bad (unknown) element prefixes are ignored. |
| [IncludeElementPrefix](#IncludeElementPrefix) | Whether to include the prefix in the element name. |
| [IncludeXMLDeclaration](#IncludeXMLDeclaration) | Whether to include the XML declaration when writing XML. |
| [Indent](#Indent) | The characters to use for each indentation level. |
| [Interrupt](#Interrupt) | Whether to stop parsing the current XML document. |
| [Offset](#Offset) | Current offset of the document being parsed. |
| [PreserveAll](#PreserveAll) | Whether to preserve processing instructions and comments. |
| [PreserveWhitespace](#PreserveWhitespace) | If true, leading and trailing whitespace in element text is preserved. |
| [ProcessNamespace](#ProcessNamespace) | Whether the parser will process namespaces. |
| [QuoteChar](#QuoteChar) | Quote character to use for attribute values. |
| [StringProcessingOptions](#StringProcessingOptions) | Defines options to use when processing string values. |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [GUIAvailable](#GUIAvailable) | Whether or not a message loop is available for processing events. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# BuildDOM Property ([XML](#xml-component) Component)

When set to true, this property creates an internal object model of the XML document.

## Syntax

```text
public bool BuildDOM { get; set; }
```

## Default Value

True

## Remarks

Set BuildDOM to *true* when you need to browse the current document through [XPath](#xpath-property-xml-component).

[Validate](#validate-property-xml-component) is automatically set to *true* when BuildDOM is set to *true*.

# InputData Property ([XML](#xml-component) Component)

This property specifies the XML data to parse.

## Syntax

```text
public string InputData { get; set; }
```

## Default Value

""

## Remarks

This property specifies the XML to be processed. Set this property before calling [Parse](#parse-method-xml-component).

This property may be set to a complete XML document or to partial data. When setting partial data, call [Parse](#parse-method-xml-component) after each chunk of data is set. For instance:

```text
//Parse the following in chunks: <test>1</test>
xml.InputData = "<test>"
xml.Parse();
xml.InputData = "1<test>"
xml.Parse();
```

**Input Properties**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

- [SetInputStream](#setinputstream-method-xml-component)
- [InputFile](#inputfile-property-xml-component)
- InputData

 When a valid source is found, the search stops.

# InputFile Property ([XML](#xml-component) Component)

This property specifies the file to process.

## Syntax

```text
public string InputFile { get; set; }
```

## Default Value

""

## Remarks

This property specifies the file to be processed. Set this property to the full or relative path to the file that will be processed.

After setting this property, call [Parse](#parse-method-xml-component) to parse the document.

**Input Properties**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

- [SetInputStream](#setinputstream-method-xml-component)
- InputFile
- [InputData](#inputdata-property-xml-component)

 When a valid source is found, the search stops.

# Namespaces Property ([XML](#xml-component) Component)

This property includes a collection of namespaces in the current namespace stack.

## Syntax

```text
public XMLNamespaceList Namespaces { get; }
```

## Remarks

This property contains a collection of XML namespaces, which are standards for providing uniquely named elements and attributes in an XML instance.

This collection is indexed from *0* to *Count - 1*.

This property is not available at design time.

 Please refer to the [XMLNamespace](#xmlnamespace-type) type for a complete list of fields.

# OutputData Property ([XML](#xml-component) Component)

The output XML after processing.

## Syntax

```text
public string OutputData { get; set; }
```

## Default Value

""

## Remarks

This property will be populated with the output from the operation if [OutputFile](#outputfile-property-xml-component) and [SetOutputStream](#setoutputstream-method-xml-component) are not set.

# OutputFile Property ([XML](#xml-component) Component)

This property includes the path to a local file where the output will be written.

## Syntax

```text
public string OutputFile { get; set; }
```

## Default Value

""

## Remarks

This property specifies the file to which the output will be written. This may be set to an absolute or relative path.

**Output Properties**

The component will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

- [SetOutputStream](#setoutputstream-method-xml-component)
- OutputFile
- [OutputData](#outputdata-property-xml-component): The output data are written to this property if no other destination is specified.

# Overwrite Property ([XML](#xml-component) Component)

This property indicates whether or not the component should overwrite files.

## Syntax

```text
public bool Overwrite { get; set; }
```

## Default Value

False

## Remarks

This property indicates whether or not the component will overwrite [OutputFile](#outputfile-property-xml-component). If Overwrite is *false*, an error will be thrown whenever [OutputFile](#outputfile-property-xml-component) exists before an operation. The default value is *false*.

# Validate Property ([XML](#xml-component) Component)

This property controls whether documents are validated during parsing.

## Syntax

```text
public bool Validate { get; set; }
```

## Default Value

True

## Remarks

When *true* (default), the document will be validated during parsing. To disable validation set Validate to *false*. Disabling validation may be useful in cases in which data can still be parsed even if the document is not well formed.

# XAttributes Property ([XML](#xml-component) Component)

This property includes a collection of attributes of the current element.

## Syntax

```text
public XMLAttributeList XAttributes { get; }
```

## Remarks

This collection consists of all attributes of the current XML element. The component parses each attribute into a collection of [XMLAttribute](#xmlattribute-type) objects.

This collection is indexed from *0* to *Count - 1*.

This property is not available at design time.

 Please refer to the [XMLAttribute](#xmlattribute-type) type for a complete list of fields.

# XChildren Property ([XML](#xml-component) Component)

This property includes a collection of child elements of the currently selected XML element.

## Syntax

```text
public XMLElementList XChildren { get; }
```

## Remarks

This property contains a collection of child elements of the currently selected XML element. The elements are provided in the collection in the same order they are found in the XML document.

This collection is indexed from *0* to *Count - 1*.

This property is not available at design time.

 Please refer to the [XMLElement](#xmlelement-type) type for a complete list of fields.

# XComments Property ([XML](#xml-component) Component)

This property includes a collection of comments of the current element.

## Syntax

```text
public XMLCommentList XComments { get; }
```

## Remarks

This collection consists of all comments of the element at the current [XPath](#xpath-property-xml-component). The component parses each comment into a collection of [XMLComment](#xmlcomment-type) objects.

This collection is indexed from *0* to *Count - 1*.

**This functionality is not yet implemented.**

This property is not available at design time.

 Please refer to the [XMLComment](#xmlcomment-type) type for a complete list of fields.

# XElement Property ([XML](#xml-component) Component)

This property includes the name of the current element.

## Syntax

```text
public string XElement { get; set; }
```

## Default Value

""

## Remarks

The current element is specified through the [XPath](#xpath-property-xml-component) property.

# XMLDeclaration Property ([XML](#xml-component) Component)

This property specifies details of the XML declaration.

## Syntax

```text
public XMLDeclaration XMLDeclaration { get; set; }
```

## Remarks

This property holds details of the XML declaration for the document being written.

This is applicable only when writing XML.

 Please refer to the [XMLDeclaration](#xmldeclaration-type) type for a complete list of fields.

# XNamespace Property ([XML](#xml-component) Component)

This property includes the namespace of the current element.

## Syntax

```text
public string XNamespace { get; set; }
```

## Default Value

""

## Remarks

The current element is specified through the [XPath](#xpath-property-xml-component) property.

# XParent Property ([XML](#xml-component) Component)

This property includes the parent of the current element.

## Syntax

```text
public string XParent { get; }
```

## Default Value

""

## Remarks

The current element is specified through the [XPath](#xpath-property-xml-component) property.

This property is read-only.

# XPath Property ([XML](#xml-component) Component)

This property provides a way to point to a specific element in the document.

## Syntax

```text
public string XPath { get; set; }
```

## Default Value

""

## Remarks

XPath implements a subset of the XML XPath specification, allowing you to point to specific elements in the XML document.

The path is a series of one or more element accessors separated by */*. The path can be absolute (starting with */*) or relative to the current XPath location.

 The following are possible values for an element accessor:

|  |  |
| --- | --- |
| 'name' | A particular element name |
| name[i] | The i-th subelement of the current element with the given name |
| [i] | The i-th subelement of the current element |
| [last()] | The last subelement of the current element |
| [last()-i] | The subelement located at the last location minus i in the current element |
| name[@attrname="attrvalue"] | The subelement containing a particular value for a given attribute (supports single AND double quotes) |
| .. | The parent of the current element |

 When XPath is set to a valid path, [XElement](#xelement-property-xml-component) points to the name of the element, with [XParent](#xparent-property-xml-component), [XNamespace](#xnamespace-property-xml-component), [XPrefix](#xprefix-property-xml-component), [XChildren](#xchildren-property-xml-component) , and [XText](#xtext-property-xml-component) providing other properties of the element. The attributes of the current element are provided in the [XAttributes](#xattributes-property-xml-component) collection.

[BuildDOM](#builddom-property-xml-component) must be set to *true* before parsing the document for the XPath functionality to be available.

**Example. Setting XPath:**

|  |  |
| --- | --- |
| Document root | XML.XPath = "/" |
| Specific Element | XML.XPath = "/root/SubElement1/SubElement2/" |
| i-th Child | XML.XPath = "/root/SubElement1[i]" |

# XPrefix Property ([XML](#xml-component) Component)

This property includes the prefix of the current element.

## Syntax

```text
public string XPrefix { get; set; }
```

## Default Value

""

## Remarks

The current element is specified through the [XPath](#xpath-property-xml-component) property.

# XSubTree Property ([XML](#xml-component) Component)

This property includes a snapshot of the current element in the document.

## Syntax

```text
public string XSubTree { get; }
```

## Default Value

""

## Remarks

The current element is specified through the [XPath](#xpath-property-xml-component) property. For this property to work, you must set [CacheContent](#CacheContent) to *true*.

This property is read-only.

# XText Property ([XML](#xml-component) Component)

This property includes the text of the current element.

## Syntax

```text
public string XText { get; set; }
```

## Default Value

""

## Remarks

The current element is specified through the [XPath](#xpath-property-xml-component) property.

The XText property can be used to update or change the content of the selected element.

**Example. Updating an element via XText:**

```text
 xml.InputData = "<person><name>John</name></person>";
 xml.Parse();
 xml.XPath = "/person/name";
 xml.XText; // John
 xml.XText = "Mary";
 xml.Save();
```

# Config Method ([XML](#xml-component) Component)

Sets or retrieves a configuration setting.

## Syntax

```text
public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);
```

## Remarks

Config is a generic method available in every component. It is used to set and retrieve [configuration settings](#config-settings-xml-component) for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these *internal properties* is provided through the Config method.

To set a configuration setting named *PROPERTY*, you must call *Config("PROPERTY=VALUE")*, where *VALUE* is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a [configuration setting](#config-settings-xml-component), you must call *Config("PROPERTY")*. The value will be returned as a string.

# EndElement Method ([XML](#xml-component) Component)

This method writes the closing tag of an open XML element.

## Syntax

```text
public void EndElement();

Async Version
public async Task EndElement();
public async Task EndElement(CancellationToken cancellationToken);
```

## Remarks

This method writes the closing tag of the XML element most recently opened using [StartElement](#startelement-method-xml-component).

If no elements are opened, the call throws an exception.

# Flush Method ([XML](#xml-component) Component)

This method flushes the parser and checks its end state.

## Syntax

```text
public void Flush();

Async Version
public async Task Flush();
public async Task Flush(CancellationToken cancellationToken);
```

## Remarks

When Flush is called, the parser flushes all its buffers, firing events as necessary, and then checks its end state. If [Validate](#validate-property-xml-component) is *true*, the parser verifies that all open elements were closed, returning an error if not.

# GetAttr Method ([XML](#xml-component) Component)

This method returns the value of the specified attribute.

## Syntax

```text
public string GetAttr(string attrName);

Async Version
public async Task<string> GetAttr(string attrName);
public async Task<string> GetAttr(string attrName, CancellationToken cancellationToken);
```

## Remarks

This method returns the value of the attribute specified by the *AttrName* parameter.

If the attribute does not exist, an empty string is returned. The behavior when an attribute does not exist is controlled by [ErrorOnEmptyAttr](#ErrorOnEmptyAttr).

Please refer to the [XAttributes](#xattributes-property-xml-component) collection for more information.

# HasXPath Method ([XML](#xml-component) Component)

This method determines whether a specific element exists in the document.

## Syntax

```text
public bool HasXPath(string XPath);

Async Version
public async Task<bool> HasXPath(string XPath);
public async Task<bool> HasXPath(string XPath, CancellationToken cancellationToken);
```

## Remarks

This method determines whether a particular XPath exists within the document. This may be used to check if a path exists before setting it through [XPath](#xpath-property-xml-component).

This method returns *true* if the *XPath* exists, and *false* if not.

See [XPath](#xpath-property-xml-component) for details on the XPath syntax.

# InsertAttr Method ([XML](#xml-component) Component)

This method inserts a new attribute into the current element.

## Syntax

```text
public void InsertAttr(string name, string namespaceURI, string value);

Async Version
public async Task InsertAttr(string name, string namespaceURI, string value);
public async Task InsertAttr(string name, string namespaceURI, string value, CancellationToken cancellationToken);
```

## Remarks

This method inserts a new attribute into the element at the current [XPath](#xpath-property-xml-component).

This method requires that [BuildDOM](#builddom-property-xml-component) is set to *true*. If the attribute specified by *Name* already exists in the current element, an error is returned. To update an existing attribute, use [SetAttr](#setattr-method-xml-component).

To write attributes when building a new document from scratch, use [PutAttr](#putattr-method-xml-component).

# InsertElement Method ([XML](#xml-component) Component)

This method inserts a new child element into the current element.

## Syntax

```text
public void InsertElement(string name, string namespaceURI, string value);

Async Version
public async Task InsertElement(string name, string namespaceURI, string value);
public async Task InsertElement(string name, string namespaceURI, string value, CancellationToken cancellationToken);
```

## Remarks

This method appends a new child element into the element at the current [XPath](#xpath-property-xml-component).

This method requires that [BuildDOM](#builddom-property-xml-component) is set to *true*. Multiple child elements with the same name may be added.

To write elements when building a new document from scratch, use [PutElement](#putelement-method-xml-component).

# Interrupt Method ([XML](#xml-component) Component)

This method interrupts the current method.

## Syntax

```text
public void Interrupt();

Async Version
public async Task Interrupt();
public async Task Interrupt(CancellationToken cancellationToken);
```

## Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

# LoadDOM Method ([XML](#xml-component) Component)

This method loads the document object model (DOM) from a file.

## Syntax

```text
public void LoadDOM(string fileName);

Async Version
public async Task LoadDOM(string fileName);
public async Task LoadDOM(string fileName, CancellationToken cancellationToken);
```

## Remarks

The LoadDOM method loads a DOM structure previously saved by [SaveDOM](#savedom-method-xml-component) from the file specified in *FileName*.

Please refer to the [SaveDOM](#savedom-method-xml-component) method for more information.

# LoadSchema Method ([XML](#xml-component) Component)

This method loads the XML schema.

## Syntax

```text
public void LoadSchema(string schema);

Async Version
public async Task LoadSchema(string schema);
public async Task LoadSchema(string schema, CancellationToken cancellationToken);
```

## Remarks

**This functionality is not yet implemented.**

This method loads the schema specified in the *Schema* parameter. The *Schema* may be specified as either a string or the path to a file on disk.

The component will validate the input data during parsing to verify whether or not it adheres to the schema.

# Parse Method ([XML](#xml-component) Component)

This method parses the specified XML data.

## Syntax

```text
public void Parse();

Async Version
public async Task Parse();
public async Task Parse(CancellationToken cancellationToken);
```

## Remarks

This method parses the specified XML data.

When parsing a document, events will fire to provide information about the parsed data. After Parse returns, the document may be navigated by setting [XPath](#xpath-property-xml-component) if [BuildDOM](#builddom-property-xml-component) is *true* (default). If [BuildDOM](#builddom-property-xml-component) is *false*, parsed data are accessible only through the events.

Events are fired only when qualifying conditions (e.g., the beginning of a new element) are met. In the meantime, text will be buffered internally. The following events will fire during parsing:

- [Characters](#characters-event-xml-component)
- [Comment](#comment-event-xml-component)
- [EndElement](#endelement-event-xml-component)
- [EndPrefixMapping](#endprefixmapping-event-xml-component)
- [EvalEntity](#evalentity-event-xml-component)
- [IgnorableWhitespace](#ignorablewhitespace-event-xml-component)
- [Meta](#meta-event-xml-component)
- [PI](#pi-event-xml-component)
- [SpecialSection](#specialsection-event-xml-component)
- [StartElement](#startelement-event-xml-component)
- [StartPrefixMapping](#startprefixmapping-event-xml-component)

If [BuildDOM](#builddom-property-xml-component) is *true* (default), [XPath](#xpath-property-xml-component) may be set after this method returns. [XPath](#xpath-property-xml-component) implements a subset of the XML XPath specification, allowing you to point to specific elements in the XML document.

The path is a series of one or more element accessors separated by */*. The path can be absolute (starting with */*) or relative to the current [XPath](#xpath-property-xml-component) location.

 The following are possible values for an element accessor:

|  |  |
| --- | --- |
| 'name' | A particular element name |
| name[i] | The i-th subelement of the current element with the given name |
| [i] | The i-th subelement of the current element |
| [last()] | The last subelement of the current element |
| [last()-i] | The subelement located at the last location minus i in the current element |
| name[@attrname="attrvalue"] | The subelement containing a particular value for a given attribute (supports single AND double quotes) |
| .. | The parent of the current element |

 When [XPath](#xpath-property-xml-component) is set to a valid path, [XElement](#xelement-property-xml-component) points to the name of the element, with [XParent](#xparent-property-xml-component), [XNamespace](#xnamespace-property-xml-component), [XPrefix](#xprefix-property-xml-component), [XChildren](#xchildren-property-xml-component) , and [XText](#xtext-property-xml-component) providing other properties of the element. The attributes of the current element are provided in the [XAttributes](#xattributes-property-xml-component) collection.

[BuildDOM](#builddom-property-xml-component) must be set to *true* before parsing the document for the [XPath](#xpath-property-xml-component) functionality to be available.

**Example. Setting XPath:**

|  |  |
| --- | --- |
| Document root | XML.XPath = "/" |
| Specific Element | XML.XPath = "/root/SubElement1/SubElement2/" |
| i-th Child | XML.XPath = "/root/SubElement1[i]" |

**Input Properties**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

- [SetInputStream](#setinputstream-method-xml-component)
- [InputFile](#inputfile-property-xml-component)
- [InputData](#inputdata-property-xml-component)

 When a valid source is found, the search stops.

If parsing multiple documents, call [Reset](#reset-method-xml-component) between documents to reset the parser.

# PutAttr Method ([XML](#xml-component) Component)

This method writes an XML attribute.

## Syntax

```text
public void PutAttr(string name, string namespaceURI, string value);

Async Version
public async Task PutAttr(string name, string namespaceURI, string value);
public async Task PutAttr(string name, string namespaceURI, string value, CancellationToken cancellationToken);
```

## Remarks

This method writes an XML attribute in the currently opened XML element. It must be called right after calling [StartElement](#startelement-method-xml-component) and before any calls to [PutString](#putstring-method-xml-component), [PutComment](#putcomment-method-xml-component), or [PutRaw](#putraw-method-xml-component).

If *Name* is a local name without a prefix, the component will automatically introduce a new xmlns="*NamespaceURI*" attribute, if necessary.

If *Name* is in the form *prefix:local*, the component will automatically introduce a new xmlns:prefix="*NamespaceURI*" as necessary.

Certain attribute names will be handled in special ways by this method. If *Name* is *xmlns* or uses the *xmlns* prefix, the attribute will be interpreted as a namespace declaration, regardless of the value of *NamespaceURI*. Similarly, any attribute using the *xml* prefix will be interpreted as a special attribute (like *xml:lang*) and *NamespaceURI* will be ignored.

To add or modify attributes in an existing parsed document, use [InsertAttr](#insertattr-method-xml-component) or [SetAttr](#setattr-method-xml-component).

# PutCData Method ([XML](#xml-component) Component)

This method writes an XML CDATA block.

## Syntax

```text
public void PutCData(string text);

Async Version
public async Task PutCData(string text);
public async Task PutCData(string text, CancellationToken cancellationToken);
```

## Remarks

This method writes a new XML CDATA block with the specified text inside the current element.

# PutComment Method ([XML](#xml-component) Component)

This method writes an XML comment block.

## Syntax

```text
public void PutComment(string text);

Async Version
public async Task PutComment(string text);
public async Task PutComment(string text, CancellationToken cancellationToken);
```

## Remarks

This method writes a new XML comment block with the specified text.

# PutElement Method ([XML](#xml-component) Component)

This method writes a simple XML element with a value.

## Syntax

```text
public void PutElement(string name, string namespaceURI, string value);

Async Version
public async Task PutElement(string name, string namespaceURI, string value);
public async Task PutElement(string name, string namespaceURI, string value, CancellationToken cancellationToken);
```

## Remarks

This method writes a simple XML element with no attributes and the specified value between the opening and closing tags. To add elements to an existing parsed document, use [InsertElement](#insertelement-method-xml-component).

If *Name* is a local name without a prefix, the component will automatically introduce a new xmlns="*NamespaceURI*" attribute, if necessary.

If *Name* is in the form *prefix:local*, the component will automatically introduce a new xmlns:prefix="*NamespaceURI*" as necessary.

When calling PutElement or [StartElement](#startelement-method-xml-component), if a *NamespaceURI* is not specified, an empty namespace will be defined for the element. If a namespace should be associated with the element, a *NamespaceURI* value must be provided. When creating the XML, the component will determine if the namespace already exists to avoid duplicate definitions of the same namespace. For example, to create this XML:

```text
<book xmlns='urn:loc.gov:books'
      xmlns:isbn='urn:ISBN:0-395-36341-6'>
    <title>Cheaper by the Dozen</title>
    <isbn:number>1568491379</isbn:number>
</book>
```

 Use the following code:

```text
xml.StartElement("book", "urn:loc.gov:books");
xml.PutAttr("xmlns:isbn", "", "urn:ISBN:0-395-36341-6");
xml.PutElement("title", "urn:loc.gov:books", "Cheaper by the Dozen");
xml.PutElement("isbn:number", "urn:ISBN:0-395-36341-6", "1568491379");
xmlw.Close();
```

 In this example, the *title* element uses the default namespace *urn:loc.gov:books* and the *number* element uses the *urn:ISBN:0-395-36341-6* namespace as defined for the *isbn* prefix.

# PutRaw Method ([XML](#xml-component) Component)

This method writes a raw XML fragment.

## Syntax

```text
public void PutRaw(string text);

Async Version
public async Task PutRaw(string text);
public async Task PutRaw(string text, CancellationToken cancellationToken);
```

## Remarks

This method writes a raw XML fragment to the output, without escaping and without verification. If an XML element opening tag has been written before the raw fragment, the fragment will be written as a child of the current element.

Use of this method should be carefully considered as it can easily lead to malformed XML content.

# PutString Method ([XML](#xml-component) Component)

This method writes text inside an XML element.

## Syntax

```text
public void PutString(string text);

Async Version
public async Task PutString(string text);
public async Task PutString(string text, CancellationToken cancellationToken);
```

## Remarks

This method will XML escape the value provided and write the resulting escaped text between the opening and closing tags of an XML element.

# RemoveAttr Method ([XML](#xml-component) Component)

This method removes an attribute from the current element.

## Syntax

```text
public void RemoveAttr(string attrName);

Async Version
public async Task RemoveAttr(string attrName);
public async Task RemoveAttr(string attrName, CancellationToken cancellationToken);
```

## Remarks

This method removes the attribute specified by *AttrName* from the element at the current [XPath](#xpath-property-xml-component). This method requires that [BuildDOM](#builddom-property-xml-component) is set to *true*. If the specified attribute does not exist in the current element, the method returns without error.

**This functionality is not yet implemented.**

# RemoveChildren Method ([XML](#xml-component) Component)

This method removes the children of the element at the specified XPath.

## Syntax

```text
public void RemoveChildren();

Async Version
public async Task RemoveChildren();
public async Task RemoveChildren(CancellationToken cancellationToken);
```

## Remarks

This method removes the children of the element specified by [XPath](#xpath-property-xml-component). This method requires that [BuildDOM](#builddom-property-xml-component) is set to *true*.

When called, the component will remove the children of the element from the internal representation of the XML (the DOM). The element itself remains, with no children. This may be used at any time after [Parse](#parse-method-xml-component) returns, or from within the [EndElement](#endelement-event-xml-component) event as a document is parsed to remove sections of a document that will not be needed later. By removing unnecessary elements from the DOM, memory consumption is reduced and overall performance is improved.

**Example. RemoveChildren:**

Given the XML:

```text
<food>
	<fruits>
		<apple>
			<color>red</color>
		</apple>
		<banana>
			<color>yellow</color>
		</banana>
	</fruits>
</food>
```

This code removes the children of the *apple* element while leaving the *apple* element in place.

```csharp
xml.XPath = "/food/fruits/apple";
xml.RemoveChildren();
```

The XML stored in the DOM is now:

```text
<food>
	<fruits>
		<apple>
		</apple>
		<banana>
			<color>yellow</color>
		</banana>
	</fruits>
</food>
```

# RemoveElement Method ([XML](#xml-component) Component)

This method removes the element at the specified XPath.

## Syntax

```text
public void RemoveElement();

Async Version
public async Task RemoveElement();
public async Task RemoveElement(CancellationToken cancellationToken);
```

## Remarks

This method removes the element specified by [XPath](#xpath-property-xml-component). This method requires that [BuildDOM](#builddom-property-xml-component) is set to *true*.

When called, the component will remove the element and its children from the internal representation of the XML (the DOM). This may be used at any time after [Parse](#parse-method-xml-component) returns, or from within the [EndElement](#endelement-event-xml-component) event as a document is parsed to remove sections of a document that will not be needed later. By removing unnecessary elements from the DOM, memory consumption is reduced and overall performance is improved.

**Example. RemoveElement:**

Given the XML:

```text
<food>
	<fruits>
		<apple>
			<color>red</color>
		</apple>
		<banana>
			<color>yellow</color>
		</banana>
	</fruits>
</food>
```

This code removes the *apple* element and its children.

```csharp
xml.XPath = "/food/fruits/apple";
xml.RemoveElement();
```

The XML stored in the DOM is now:

```text
<food>
	<fruits>
		<banana>
			<color>yellow</color>
		</banana>
	</fruits>
</food>
```

# Reset Method ([XML](#xml-component) Component)

This method resets the parser.

## Syntax

```text
public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);
```

## Remarks

When called, the parser flushes all its buffers, firing events as necessary, and then initializes itself to its default state.

Reset must also be used as a signal to the parser that the current stream of text has terminated.

# Save Method ([XML](#xml-component) Component)

This method saves the current XML output.

## Syntax

```text
public void Save();

Async Version
public async Task Save();
public async Task Save(CancellationToken cancellationToken);
```

## Remarks

When used with the streaming writer (e.g., after [StartElement](#startelement-method-xml-component) and [EndElement](#endelement-method-xml-component) calls), this method closes any open XML elements and then closes the [OutputFile](#outputfile-property-xml-component) or output stream if necessary.

When used after parsing and modifying a document via the DOM (e.g., after [InsertAttr](#insertattr-method-xml-component), [InsertElement](#insertelement-method-xml-component), [SetAttr](#setattr-method-xml-component), [RemoveAttr](#removeattr-method-xml-component), [RemoveElement](#removeelement-method-xml-component), or [RemoveChildren](#removechildren-method-xml-component)), this method serializes the modified DOM to [OutputFile](#outputfile-property-xml-component) or the output stream.

# SaveDOM Method ([XML](#xml-component) Component)

This method saves the DOM to a file.

## Syntax

```text
public void SaveDOM(string fileName);

Async Version
public async Task SaveDOM(string fileName);
public async Task SaveDOM(string fileName, CancellationToken cancellationToken);
```

## Remarks

The SaveDOM method saves the current DOM structure to the file specified in *FileName*. This enables the component to later load the DOM without incurring any parsing overhead.

Please refer to the [LoadDOM](#loaddom-method-xml-component) method for more information.

# SetAttr Method ([XML](#xml-component) Component)

This method sets the value of an existing attribute in the current element.

## Syntax

```text
public void SetAttr(string name, string namespaceURI, string value);

Async Version
public async Task SetAttr(string name, string namespaceURI, string value);
public async Task SetAttr(string name, string namespaceURI, string value, CancellationToken cancellationToken);
```

## Remarks

This method updates the value of an attribute in the element at the current [XPath](#xpath-property-xml-component).

This method requires that [BuildDOM](#builddom-property-xml-component) is set to *true*. If the attribute specified by *Name* does not already exist in the current element, an error is returned. To add a new attribute, use [InsertAttr](#insertattr-method-xml-component).

# SetInputStream Method ([XML](#xml-component) Component)

This method sets the stream from which the component will read data to parse.

## Syntax

```text
public void SetInputStream(System.IO.Stream inputStream);

Async Version
public async Task SetInputStream(System.IO.Stream inputStream);
public async Task SetInputStream(System.IO.Stream inputStream, CancellationToken cancellationToken);
```

## Remarks

This method specifies a stream from which data will be read when [Parse](#parse-method-xml-component) is called.

**Input Properties**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

- SetInputStream
- [InputFile](#inputfile-property-xml-component)
- [InputData](#inputdata-property-xml-component)

 When a valid source is found, the search stops.

# SetOutputStream Method ([XML](#xml-component) Component)

This method sets the stream to which the component will write the XML.

## Syntax

```text
public void SetOutputStream(System.IO.Stream outputStream);

Async Version
public async Task SetOutputStream(System.IO.Stream outputStream);
public async Task SetOutputStream(System.IO.Stream outputStream, CancellationToken cancellationToken);
```

## Remarks

This method sets the stream to which output will be written when writing data.

**Output Properties**

The component will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

- SetOutputStream
- [OutputFile](#outputfile-property-xml-component)
- [OutputData](#outputdata-property-xml-component): The output data are written to this property if no other destination is specified.

# StartElement Method ([XML](#xml-component) Component)

This method writes the opening tag of an XML element.

## Syntax

```text
public void StartElement(string name, string namespaceURI);

Async Version
public async Task StartElement(string name, string namespaceURI);
public async Task StartElement(string name, string namespaceURI, CancellationToken cancellationToken);
```

## Remarks

This method writes the opening tag of a new XML element. If an XML element is already opened, then this element is written as a child.

If *Name* is a local name without a prefix, the component will automatically introduce a new xmlns="*NamespaceURI*" attribute, if necessary.

If *Name* is in the form *prefix:local*, the component will automatically introduce a new xmlns:prefix="*NamespaceURI*" as necessary.

When calling [PutElement](#putelement-method-xml-component) or StartElement, if a *NamespaceURI* is not specified, an empty namespace will be defined for the element. If a namespace should be associated with the element, a *NamespaceURI* value must be provided. When creating the XML, the component will determine if the namespace already exists to avoid duplicate definitions of the same namespace. For example, to create this XML:

```text
<book xmlns='urn:loc.gov:books'
      xmlns:isbn='urn:ISBN:0-395-36341-6'>
    <title>Cheaper by the Dozen</title>
    <isbn:number>1568491379</isbn:number>
</book>
```

 Use the following code:

```text
xml.StartElement("book", "urn:loc.gov:books");
xml.PutAttr("xmlns:isbn", "", "urn:ISBN:0-395-36341-6");
xml.PutElement("title", "urn:loc.gov:books", "Cheaper by the Dozen");
xml.PutElement("isbn:number", "urn:ISBN:0-395-36341-6", "1568491379");
xmlw.Close();
```

 In this example, the *title* element uses the default namespace *urn:loc.gov:books* and the *number* element uses the *urn:ISBN:0-395-36341-6* namespace as defined for the *isbn* prefix.

# TryXPath Method ([XML](#xml-component) Component)

This method navigates to the specified XPath if it exists.

## Syntax

```text
public bool TryXPath(string xpath);

Async Version
public async Task<bool> TryXPath(string xpath);
public async Task<bool> TryXPath(string xpath, CancellationToken cancellationToken);
```

## Remarks

This method will attempt to navigate to the specified *XPath* parameter if it exists within the document.

If the XPath exists, the [XPath](#xpath-property-xml-component) property will be updated and this method returns *true*.

If the XPath does not exist, the [XPath](#xpath-property-xml-component) property is not updated and this method returns *false*.

# Characters Event ([XML](#xml-component) Component)

This event is fired for plaintext segments of the input stream.

## Syntax

```text
public event OnCharactersHandler OnCharacters;

public delegate void OnCharactersHandler(object sender, XMLCharactersEventArgs e);

public class XMLCharactersEventArgs : EventArgs {
  public string Text { get; }
}
```

## Remarks

The Characters event provides the plaintext content of the XML document (i.e., the text inside the tags). The text is provided through the *Text* parameter.

The text includes whitespace as well as end-of-line characters, except for ignorable whitespace, which is fired through the [IgnorableWhitespace](#ignorablewhitespace-event-xml-component) event.

# Comment Event ([XML](#xml-component) Component)

This event is fired when a comment section is encountered.

## Syntax

```text
public event OnCommentHandler OnComment;

public delegate void OnCommentHandler(object sender, XMLCommentEventArgs e);

public class XMLCommentEventArgs : EventArgs {
  public string Text { get; }
}
```

## Remarks

The Comment event is fired whenever a comment section (*<!-- ...text... -->*) is found in the document.

The full text of the comment is provided by the *Text* parameter.

# EndElement Event ([XML](#xml-component) Component)

This event is fired when an end-element tag is encountered.

## Syntax

```text
public event OnEndElementHandler OnEndElement;

public delegate void OnEndElementHandler(object sender, XMLEndElementEventArgs e);

public class XMLEndElementEventArgs : EventArgs {
  public string Namespace { get; }
  public string Element { get; }
  public string QName { get; }
  public bool IsEmpty { get; }
}
```

## Remarks

The EndElement event is fired when an end-element tag is found in the document.

The element name is provided by the *Element* parameter.

The *IsEmpty* parameter is *true* when the event corresponds to an empty element declaration.

# EndPrefixMapping Event ([XML](#xml-component) Component)

This event is fired when leaving the scope of a namespace declaration.

## Syntax

```text
public event OnEndPrefixMappingHandler OnEndPrefixMapping;

public delegate void OnEndPrefixMappingHandler(object sender, XMLEndPrefixMappingEventArgs e);

public class XMLEndPrefixMappingEventArgs : EventArgs {
  public string Prefix { get; }
}
```

## Remarks

The [StartPrefixMapping](#startprefixmapping-event-xml-component) event is fired when entering the scope of a namespace declaration.

# Error Event ([XML](#xml-component) Component)

Fired when information is available about errors during data delivery.

## Syntax

```text
public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, XMLErrorEventArgs e);

public class XMLErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}
```

## Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component throws an exception.

The *ErrorCode* parameter contains an error code, and the *Description* parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the [Error Codes](#trappable-errors-xml-component) section.

# EvalEntity Event ([XML](#xml-component) Component)

This event is fired every time an entity needs to be evaluated.

## Syntax

```text
public event OnEvalEntityHandler OnEvalEntity;

public delegate void OnEvalEntityHandler(object sender, XMLEvalEntityEventArgs e);

public class XMLEvalEntityEventArgs : EventArgs {
  public string Entity { get; }
  public string Value { get; set; }
}
```

## Remarks

The *Value* parameter contains a suggested value for the entity (normally the entity name itself). You may set *Value* to a value of your choice, which will later be passed into the text stream.

# IgnorableWhitespace Event ([XML](#xml-component) Component)

This event is fired when a section of ignorable whitespace is encountered.

## Syntax

```text
public event OnIgnorableWhitespaceHandler OnIgnorableWhitespace;

public delegate void OnIgnorableWhitespaceHandler(object sender, XMLIgnorableWhitespaceEventArgs e);

public class XMLIgnorableWhitespaceEventArgs : EventArgs {
  public string Text { get; }
}
```

## Remarks

The ignorable whitespace section is provided by the *Text* parameter.

# Meta Event ([XML](#xml-component) Component)

This event fires when a meta section is encountered.

## Syntax

```text
public event OnMetaHandler OnMeta;

public delegate void OnMetaHandler(object sender, XMLMetaEventArgs e);

public class XMLMetaEventArgs : EventArgs {
  public string Text { get; }
}
```

## Remarks

The Meta event is fired whenever a meta information section (*<! ...text... >*) is found in the document.

The full text of the meta section is provided by the *Text* parameter.

# PI Event ([XML](#xml-component) Component)

This event is fired when a processing instruction section is encountered.

## Syntax

```text
public event OnPIHandler OnPI;

public delegate void OnPIHandler(object sender, XMLPIEventArgs e);

public class XMLPIEventArgs : EventArgs {
  public string Text { get; }
}
```

## Remarks

The PI event is fired whenever a processing instruction section (*<? ...text... ?>*) is found in the document.

The full text of the processing instruction is provided by the *Text* parameter.

# SpecialSection Event ([XML](#xml-component) Component)

This event is fired when a special section is encountered.

## Syntax

```text
public event OnSpecialSectionHandler OnSpecialSection;

public delegate void OnSpecialSectionHandler(object sender, XMLSpecialSectionEventArgs e);

public class XMLSpecialSectionEventArgs : EventArgs {
  public string SectionId { get; }
  public string Text { get; }
}
```

## Remarks

The SpecialSection event is fired whenever a special section (such as *<![ CDATA [ ...text... ]]>*) is found in the document.

The full text of the special section is provided by the *Text* parameter, and the *SectionId* parameter provides the section identifier (e.g., *CDATA*).

# StartElement Event ([XML](#xml-component) Component)

This event is fired when a begin-element tag is encountered in the document.

## Syntax

```text
public event OnStartElementHandler OnStartElement;

public delegate void OnStartElementHandler(object sender, XMLStartElementEventArgs e);

public class XMLStartElementEventArgs : EventArgs {
  public string Namespace { get; }
  public string Element { get; }
  public string QName { get; }
  public bool IsEmpty { get; }
}
```

## Remarks

The StartElement event is fired when a begin-element tag is found in the document.

The element name is provided through the *Element* parameter. The attribute names and values (if any) are provided through the [XAttributes](#xattributes-property-xml-component) collection.

The *IsEmpty* parameter is *true* when the event corresponds to an empty element declaration.

# StartPrefixMapping Event ([XML](#xml-component) Component)

This event is fired when entering the scope of a namespace declaration.

## Syntax

```text
public event OnStartPrefixMappingHandler OnStartPrefixMapping;

public delegate void OnStartPrefixMappingHandler(object sender, XMLStartPrefixMappingEventArgs e);

public class XMLStartPrefixMappingEventArgs : EventArgs {
  public string Prefix { get; }
  public string URI { get; }
}
```

## Remarks

The [EndPrefixMapping](#endprefixmapping-event-xml-component) event is fired when leaving the scope of a namespace declaration.

# XML Event ([XML](#xml-component) Component)

This event is fired as XML is written.

## Syntax

```text
public event OnXMLHandler OnXML;

public delegate void OnXMLHandler(object sender, XMLXMLEventArgs e);

public class XMLXMLEventArgs : EventArgs {
  public string Text { get; }
}
```

## Remarks

This event is fired when XML is output. The *Text* parameter holds the data being written.

**This functionality is not yet implemented.**

# XMLAttribute Type

This type describes an XML attribute from the current XML element.

## Remarks

This type describes an XML attribute from the current element. It includes fields to denote information about the attribute being defined.

The following fields are available:

- [Name](#XMLAttribute_f_Name)

- [Namespace](#XMLAttribute_f_Namespace)

- [Prefix](#XMLAttribute_f_Prefix)

- [Value](#XMLAttribute_f_Value)

## Fields

 **Name** *string (read-only)*
Default: ""

The [Name](#XMLAttribute_f_Name) provides the local name (without prefix) of the attribute.

 **Namespace** *string (read-only)*
Default: ""

This field contains the attribute namespace.

 **Prefix** *string (read-only)*
Default: ""

This field contains the attribute prefix (if any). If the attribute does not have a prefix, this field is empty.

 **Value** *string (read-only)*
Default: ""

This field contains the attribute value.

## Constructors

```text
public XMLAttribute();
```

# XMLComment Type

This type holds a comment within the document.

## Remarks

This type holds a comment within the XML document.

The following fields are available:

- [Text](#XMLComment_f_Text)

## Fields

 **Text** *string*
Default: ""

This field holds the comment text.

## Constructors

```text
public XMLComment();
```

```text
public XMLComment(string text);
```

# XMLDeclaration Type

This type includes the XML declaration present at the beginning of a document.

## Remarks

This type contains details about the XML declaration, which may be set before writing a document. This is applicable only when writing documents.

The following fields are available:

- [Encoding](#XMLDeclaration_f_Encoding)

- [Standalone](#XMLDeclaration_f_Standalone)

- [Version](#XMLDeclaration_f_Version)

## Fields

 **Encoding** *string*
Default: "utf-8"

This field specifies the XML encoding to use.

This may be set before writing a document. The default value is *UTF-8*.

This is applicable only when writing XML.

 **Standalone** *bool*
Default: True

This field indicates whether the standalone attribute is present in the declaration with a value of *true*.

This may be set before writing a document. The default value is *true*.

This is applicable only when writing XML.

 **Version** *string*
Default: "1.0"

This field specifies the XML version.

This may be set before writing a document. The default value is *1.0*.

This is applicable only when writing XML.

## Constructors

```text
public XMLDeclaration();
```

```text
public XMLDeclaration(string version, string encoding, bool standalone);
```

# XMLElement Type

This type describes an element contained within the XML document.

## Remarks

This type describes an XML element. The fields for this type describe the element [Name](#XMLElement_f_Name), [Prefix](#XMLElement_f_Prefix), and [Namespace](#XMLElement_f_Namespace) of the given element.

The elements are inserted into the array in the same order they are found in the document.

The following fields are available:

- [Name](#XMLElement_f_Name)

- [Namespace](#XMLElement_f_Namespace)

- [Prefix](#XMLElement_f_Prefix)

- [XText](#XMLElement_f_XText)

## Fields

 **Name** *string (read-only)*
Default: ""

The [Name](#XMLElement_f_Name) field provides the local name (without a prefix) of the element.

 **Namespace** *string (read-only)*
Default: ""

This field contains the namespace of the element.

 **Prefix** *string (read-only)*
Default: ""

This field contains the prefix of the element (if any). If the element does not have a prefix, this field is empty.

 **XText** *string (read-only)*
Default: ""

This field contains the inner text of the element.

## Constructors

```text
public XMLElement();
```

# XMLNamespace Type

This type describes an XML namespace from the current namespace stack.

## Remarks

This type describes an XML namespace from the current stack. It includes fields to denote the [Prefix](#XMLNamespace_f_Prefix) and the [URI](#XMLNamespace_f_URI) of the namespace being defined.

The default namespace exists at index *0*. The [Prefix](#XMLNamespace_f_Prefix) field at index *0* is *xmlns*, and the [Name](#XMLNamespace_f_Name) field contains the default namespace.

The following fields are available:

- [Prefix](#XMLNamespace_f_Prefix)

- [URI](#XMLNamespace_f_URI)

## Fields

 **Prefix** *string*
Default: ""

This field contains the [Prefix](#XMLNamespace_f_Prefix) for the namespace.

 **URI** *string*
Default: ""

This field contains the namespace URI associated with the corresponding [Prefix](#XMLNamespace_f_Prefix). This URL is usually pointing to the XML schema for the namespace.

## Constructors

```text
public XMLNamespace();
```

```text
public XMLNamespace(string URI, string prefix);
```

# Config Settings ([XML](#xml-component) Component)

 The component accepts one or more of the following *configuration settings*. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these *internal properties* is provided through the [Config](#config-method-xml-component) method.

### XML Config Settings

**CacheContent**: If true, the original XML is saved in a buffer.This configuration setting controls whether or not the component retains the entire original XML in a buffer. This is used to retain the original XML as opposed to returning generated XML after parsing. The default value is *true*.

**Charset**: Specifies the charset used when encoding data.This configuration setting specifies the character set used when encoding data. This value will also be used when creating the [XMLDeclaration](#xmldeclaration-property-xml-component). The default value is *utf-8*.

**CloseInputStreamAfterProcess**: Determines whether or not the input stream is closed after processing.This configuration setting determines whether or not the input stream set by [SetInputStream](#setinputstream-method-xml-component) is closed after processing is complete. The default value is *true*.

**CloseOutputStreamAfterProcess**: Determines whether or not the output stream is closed after processing.This configuration setting determines whether or not the output stream set by [SetOutputStream](#setoutputstream-method-xml-component) is closed after processing is complete. The default value is *true*.

**EOL**: The characters to use for separating lines.If specified, the component will format the output XML using the specified characters to separate multiple lines for nested XML elements. The default value is CRLF (*"\r\n"*) .

This option should be combined with [Indent](#Indent) for full effect.

**ErrorOnEmptyAttr**: If true, passing an invalid attribute to the GetAttr method will throw an exception.If an invalid attribute name is passed to the [GetAttr](#getattr-method-xml-component) method, the method will return an empty string if this is set to *false*; otherwise, an exception is thrown.

**ExtraNameChars**: Extra characters for the parser to consider as name characters.Normally, the parser considers only the following characters as part of an XML identifier: *A* through *Z*, *a* through *z*, *0* through *9*, *0x0300* through *0x036F*, *0x203F* through *0x2040*, and *.*, *-*, *_*, and *:*.

If you would like any other characters to be considered as name characters, you may set them as a string into this property.

**ExtraSpaceChars**: Extra characters for the parser to consider as whitespace.Normally, the parser considers only the following characters as whitespace: * * (space), *\t* (tab), *\n* (newline), *\r* (carriage return), *\f* (form feed), and *\v* (vertical tab).

If you would like any other characters to be considered as whitespace, you may set them as a string into this property.

**FlushOnEOL**: If set, the parser flushes its text buffer after every line of text.The [FlushOnEOL](#FlushOnEOL) property controls whether or not [Characters](#characters-event-xml-component) events are fired for every line of the input text stream. Normally, lines are buffered internally and delivered in batches, but if the [FlushOnEOL](#FlushOnEOL) flag is set, then a [Characters](#characters-event-xml-component) event is fired for each line.

**IgnoreBadAttributePrefixes**: If true, bad (unknown) attribute prefixes are ignored.Normally a trappable error is generated when an unknown attribute prefix is encountered. This configuration setting suppresses the error. The default value is *true*.

**IgnoreBadElementPrefixes**: If true, bad (unknown) element prefixes are ignored.Normally a trappable error is generated when an unknown element prefix is encountered. This configuration setting suppresses the error. The default value is *true*.

**IncludeElementPrefix**: Whether to include the prefix in the element name.This configuration setting specifies whether or not to include the element prefix in the *Element* parameter of the [StartElement](#startelement-event-xml-component) and [EndElement](#endelement-event-xml-component) events.

If *false* (default) and [Validate](#validate-property-xml-component) is set to *false*, the prefix is included in the *Element* parameter (e.g., *ds:DigestMethod*).

If *true* and [Validate](#validate-property-xml-component) is set to *false*, the prefix is not included in the *Element* parameter (e.g., *DigestMethod*).

This setting is applicable only when [Validate](#validate-property-xml-component) is *false*.

**IncludeXMLDeclaration**: Whether to include the XML declaration when writing XML.This configuration setting specifies whether the XML declaration is included in the output XML when writing XML. When set to *true* (default), the XML declaration will be included above any user-specified XML. For instance:

```text
<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
...
```

**Indent**: The characters to use for each indentation level.If specified, the component will format the output XML using the specified characters to denote each indentation level for nested XML elements.

This option should be combined with [EOL](#EOL) for full effect.

**Interrupt**: Whether to stop parsing the current XML document.This configuration setting can be called from within any event to stop further parsing of the document. The configuration setting only works from within events. For example:

```text
void xml_OnStartElement(object sender, XMLStartElementEventArgs e)
{
  xml.Config("Interrupt");
}
```

**Offset**: Current offset of the document being parsed.This property is useful for determining the location of possible XML errors in the document.

[Offset](#Offset) values start at *1*.

**PreserveAll**: Whether to preserve processing instructions and comments.When set to *true*, the parser will preserve all processing instructions and comments of the input. The default value is *false*.

This configuration setting can be used together with [ProcessNamespace](#ProcessNamespace) when filling XML templates.

**PreserveWhitespace**: If true, leading and trailing whitespace in element text is preserved.Normally, the leading and trailing whitespace from an element's text is trimmed. When this property is set to *true*, this leading and trailing whitespace is preserved. The default value is *false*.

**ProcessNamespace**: Whether the parser will process namespaces.When set to *false*, namespaces will not be parsed or processed. This allows the original namespace information to be preserved as it appeared in the input. The default value is *true*.

This configuration setting can be used together with [PreserveAll](#PreserveAll) when filling XML templates.

**QuoteChar**: Quote character to use for attribute values.By default, the component will use double quotes around attribute values. This property can be used to specify a different character, such as a single quote.

**StringProcessingOptions**: Defines options to use when processing string values.This configuration setting determines what additional processing is performed on string values fired through the [Characters](#characters-event-xml-component) event.

NOTE: This applies only when [BuildDOM](#builddom-property-xml-component) is *false*.

By default, no additional processing is performed and the string is returned as is from the document. Strings may also be XML unescaped. Possible values are as follows:

|  |  |
| --- | --- |
| 0 (none - default) | No additional processing is performed. |
| 1 | Strings are XML unescaped. |

For instance, when set to *0*, the following text may be fired through the [Characters](#characters-event-xml-component) event:

*&"<>*

When set to *1*, the following text would be fired through the [Characters](#characters-event-xml-component) event:

*&"<>*

### Base Config Settings

**BuildInfo**: Information about the product's build.When queried, this setting will return a string containing information about the product's build.

**GUIAvailable**: Whether or not a message loop is available for processing events.In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The component will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting [GUIAvailable](#GUIAvailable) to *false* will ensure that the component does not attempt to process external events.

**LicenseInfo**: Information about the current license.When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

- Product: The product the license is for.
- Product Key: The key the license was generated from.
- License Source: Where the license was found (e.g., RuntimeLicense, License File).
- License Type: The type of license installed (e.g., Royalty Free, Single Server).
- Last Valid Build: The last valid build number for which the license will work.

**MaskSensitiveData**: Whether sensitive data is masked in log messages.In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to *true* to mask sensitive data. The default is *true*.

**UseInternalSecurityAPI**: Whether or not to use the system security libraries or an internal implementation. When set to *false*, the component will use the system security libraries by default to perform cryptographic functions where applicable. In this case, calls to unmanaged code will be made. In certain environments, this is not desirable. To use a completely managed security implementation, set this setting to *true*.

Setting this configuration setting to *true* tells the component to use the internal implementation instead of using the system security libraries.

 On Windows, this setting is set to *false* by default. On Linux/macOS, this setting is set to *true* by default.

NOTE: This setting is static. The value set is applicable to all components used in the application.

When this value is set, the product's system dynamic link library (DLL) is no longer required as a reference, as all unmanaged code is stored in that file.

# Trappable Errors ([XML](#xml-component) Component)

### XML Errors

|  |  |
| --- | --- |
| 101 | Invalid attribute index. |
| 102 | No attributes available. |
| 103 | Invalid namespace index. |
| 104 | No namespaces available. |
| 105 | Invalid element index. |
| 106 | No elements available. |
| 107 | Attribute does not exist. |
| 201 | Unbalanced element tag. |
| 202 | Unknown element prefix (cannot find namespace). |
| 203 | Unknown attribute prefix (cannot find namespace). |
| 204 | Invalid XML markup. |
| 205 | Invalid end state for parser. |
| 206 | Document contains unbalanced elements. |
| 207 | Invalid [XPath](#xpath-property-xml-component). |
| 208 | No such child. |
| 209 | Top element does not match start of path. |
| 210 | DOM tree unavailable (set [BuildDOM](#builddom-property-xml-component) to true and reparse). |
| 302 | Cannot open file. |
| 401 | Invalid XML would be generated. |
| 402 | An invalid XML name has been specified. |