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IPWorks 2022 Delphi Edition

Version 22.0 [Build 8171]

XML Component

Properties   Methods   Events   Configuration Settings   Errors  

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

Syntax

TipwXML

Remarks

The XML component can operate as either a parser of 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 mechanism that supports a subset of the XPath specification.

The parser is optimized for read applications, with a very fast engine that builds internal DOM structures with close to zero heap allocations. Additionally, BuildDOM can be set to False which reduces the overhead of creating the DOM and offers a fast forward-only parsing implementation which fires events to provide the parsed 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 if BuildDOM is True (default). If BuildDOM is False parsed data is only accessible through the events.

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

If BuildDOM is True (default), XPath may be set after this method returns. XPath implements a subset of the XML XPath specification, allowing you to point to specific elements in the XML documents.

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 points to the name of the element, with XParent, XNamespace, XPrefix, Name, Namespace, Prefix, XText, and XText providing other properties of the element. The attributes of the current element are provided in the Name, Namespace, Prefix, and Value properties.

BuildDOM must be set to True prior to parsing the document for the XPath functionality to be available.

Example (Setting XPath):

Document rootXML.XPath = "/"
Specific ElementXML.XPath = "/root/SubElement1/SubElement2/"
i-th ChildXML.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:

When a valid source is found the search stops.

If parsing multiple documents call Reset 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 to False. In this case, events will be fired as elements, entities, etc. 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 file, or to OutputData.

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:

  • OutputFile
  • OutputData: The output data is written to this property if no other destination is specified.

To begin writing the XML document first optionally set XMLDeclaration. 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 will open an element with the specified name. To create a nested structure continue calling StartElement to open more child elements. To write a value within an element call PutString. To close the element that was last opened call EndElement. Each time EndElement is called the element at the current level is closed. Alternatively, calling PutElement will write the element specified with the value specified and will also close the element.

To write an attribute of the current element, after calling StartElement call PutAttr. Call PutAttr multiple times to add multiple attributes.

Writing comments or CDATA can be done at any time with the PutComment and PutCData methods.

To close your XML document call Save. You can call Save 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.

BuildDOMWhen True, an internal object model of the XML document is created.
InputDataThe XML data to parse.
InputFileThe file to process.
NamespacesCollection of namespaces in the current namespace stack.
OutputDataThe output XML after processing.
OutputFileThe path to a local file where the output will be written.
OverwriteIndicates whether or not the component should overwrite files.
ValidateWhen True, the parser checks that the document consists of well-formed XML.
XAttributesA collection of attributes of the current element.
XChildrenCollection of child elements of the currently selected XML element.
XCommentsA collection of comments of the current element.
XElementThe name of the current element.
XMLDeclarationSpecifies details of the XML declaration.
XNamespaceThe namespace of the current element.
XParentThe parent of the current element.
XPathProvides a way to point to a specific element in the document.
XPrefixThe prefix of the current element.
XSubTreeA snapshot of the current element in the document.
XTextThe 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.

ConfigSets or retrieves a configuration setting.
EndElementWrites the closing tag of an open XML element.
FlushFlushes the parser and checks its end state.
GetAttrReturns the value of the specified attribute.
HasXPathDetermines whether a specific element exists in the document.
LoadDOMLoads the DOM from a file.
LoadSchemaLoad the XML schema.
ParseThis method parses the specified XML data.
PutAttrWrites an XML attribute.
PutCDataWrites an XML CDATA block.
PutCommentWrites an XML comment block.
PutElementWrites a simple XML element with a value.
PutRawWrites a raw XML fragment.
PutStringWrites text inside an XML element.
RemoveAttrRemove a attribute.
RemoveChildrenRemoves the children of the elment as the specified XPath.
RemoveElementRemoves the elment as the specified XPath.
ResetResets the parser.
SaveCloses the component writing stream.
SaveDOMSaves the DOM to a file.
SetInputStreamSets the stream from which the component will read data to parse.
SetOutputStreamThe stream to which the component will write the XML.
StartElementWrites the opening tag of an XML element.
TryXPathNavigates 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.

CharactersFired for plain text segments of the input stream.
CommentFired when a comment section is encountered.
EndElementFired when an end-element tag is encountered.
EndPrefixMappingFired when leaving the scope of a namespace declaration.
ErrorInformation about errors during data delivery.
EvalEntityFired every time an entity needs to be evaluated.
IgnorableWhitespaceFired when a section of ignorable whitespace is encountered.
MetaFired when a meta section is encountered.
PIFired when a processing instruction section is encountered.
SpecialSectionFired when a special section is encountered.
StartElementFired when a begin-element tag is encountered in the document.
StartPrefixMappingFired when entering the scope of a namespace declaration.
XMLFires as XML is written.

Configuration Settings


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

CacheContentIf true, the original XML is saved in a buffer.
CharsetSpecifies the charset used when encoding data.
EOLThe characters to use for separating lines.
ErrorOnEmptyAttrIf true, passing an invalid attribute to the Attr method will throw an exception.
ExtraNameCharsExtra characters for the parser to consider as name characters.
ExtraSpaceCharsExtra characters for the parser to consider as white space.
FlushOnEOLIf set, the parser flushes its text buffer after every line of text.
IgnoreBadAttributePrefixesIf true, bad (unknown) attribute prefixes are ignored.
IgnoreBadElementPrefixesIf true, bad (unknown) element prefixes are ignored.
IncludeElementPrefixWhether to include the prefix in the element name.
IncludeXMLDeclarationWhether to include the XML declaration when writing XML.
IndentThe characters to use for each indentation level.
OffsetCurrent offset of the document being parsed.
PreserveWhitespaceIf true, leading and trailing whitespace in element text is preserved.
QuoteCharQuote character to use for attribute values.
StringProcessingOptionsDefines options to use when processing string values.
BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
UseInternalSecurityAPITells the component whether or not to use the system security libraries or an internal implementation.

BuildDOM Property (XML Component)

When True, an internal object model of the XML document is created.

Syntax

property BuildDOM: Boolean read get_BuildDOM write set_BuildDOM;

Default Value

true

Remarks

Set BuildDOM to True when you need to browse the current document through XPath.

Validate is automatically set to True when BuildDOM is set to True.

InputData Property (XML Component)

The XML data to parse.

Syntax

property InputData: String read get_InputData write set_InputData;

Default Value

''

Remarks

This property specifies the XML to be processed. Set this property before calling Parse.

This may be set to a complete XML document, or partial data. When setting partial data call Parse after each chunk of data is set. For instance:

//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:

When a valid source is found the search stops.

InputFile Property (XML Component)

The file to process.

Syntax

property InputFile: String read get_InputFile write set_InputFile;

Default Value

''

Remarks

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

After setting this property call Parse 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:

When a valid source is found the search stops.

Namespaces Property (XML Component)

Collection of namespaces in the current namespace stack.

Syntax

property Namespaces: TipwXMLNamespaceList read get_Namespaces write set_Namespaces;

Remarks

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

This property is not available at design time.

OutputData Property (XML Component)

The output XML after processing.

Syntax

property OutputData: String read get_OutputData write set_OutputData;

Default Value

''

Remarks

This property will be populated with the output from the operation if OutputFile is not set.

OutputFile Property (XML Component)

The path to a local file where the output will be written.

Syntax

property OutputFile: String read get_OutputFile write set_OutputFile;

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:

  • OutputFile
  • OutputData: The output data is written to this property if no other destination is specified.

Overwrite Property (XML Component)

Indicates whether or not the component should overwrite files.

Syntax

property Overwrite: Boolean read get_Overwrite write set_Overwrite;

Default Value

false

Remarks

This property indicates whether or not the component will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.

Validate Property (XML Component)

When True, the parser checks that the document consists of well-formed XML.

Syntax

property Validate: Boolean read get_Validate write set_Validate;

Default Value

true

Remarks

You can set Validate to False when you want to ignore XML format rules (e.g. while parsing HTML files).

XAttributes Property (XML Component)

A collection of attributes of the current element.

Syntax

property XAttributes: TipwXMLAttributeList read get_XAttributes write set_XAttributes;

Remarks

This collection consists of all attributes of the current XML element. The component parses each attribute into a collection of XMLAttribute types.

This property is not available at design time.

XChildren Property (XML Component)

Collection of child elements of the currently selected XML element.

Syntax

property XChildren: TipwXMLElementList read get_XChildren write set_XChildren;

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 property is not available at design time.

XComments Property (XML Component)

A collection of comments of the current element.

Syntax

property XComments: TipwXMLCommentList read get_XComments write set_XComments;

Remarks

This collection consists of all comments of the element at the current XPath. The component parses each comment into a collection of XMLComment types.

This functionality is not yet implemented.

This property is not available at design time.

XElement Property (XML Component)

The name of the current element.

Syntax

property XElement: String read get_XElement write set_XElement;

Default Value

''

Remarks

The current element is specified via the XPath property.

XMLDeclaration Property (XML Component)

Specifies details of the XML declaration.

Syntax

property XMLDeclaration: TipwXMLDeclaration read get_XMLDeclaration write set_XMLDeclaration;

Remarks

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

This is only applicable when writing XML.

XNamespace Property (XML Component)

The namespace of the current element.

Syntax

property XNamespace: String read get_XNamespace write set_XNamespace;

Default Value

''

Remarks

The current element is specified via the XPath property.

XParent Property (XML Component)

The parent of the current element.

Syntax

property XParent: String read get_XParent;

Default Value

''

Remarks

The current element is specified via the XPath property.

This property is read-only.

XPath Property (XML Component)

Provides a way to point to a specific element in the document.

Syntax

property XPath: String read get_XPath write set_XPath;

Default Value

''

Remarks

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

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 points to the name of the element, with XParent, XNamespace, XPrefix, Name, Namespace, Prefix, XText, and XText providing other properties of the element. The attributes of the current element are provided in the Name, Namespace, Prefix, and Value properties.

BuildDOM must be set to True prior to parsing the document for the XPath functionality to be available.

Example (Setting XPath):

Document rootXML.XPath = "/"
Specific ElementXML.XPath = "/root/SubElement1/SubElement2/"
i-th ChildXML.XPath = "/root/SubElement1[i]"

XPrefix Property (XML Component)

The prefix of the current element.

Syntax

property XPrefix: String read get_XPrefix write set_XPrefix;

Default Value

''

Remarks

The current element is specified via the XPath property.

XSubTree Property (XML Component)

A snapshot of the current element in the document.

Syntax

property XSubTree: String read get_XSubTree;

Default Value

''

Remarks

The current element is specified via the XPath property. In order for this property to work you must have the CacheContent set to true.

This property is read-only.

XText Property (XML Component)

The text of the current element.

Syntax

property XText: String read get_XText write set_XText;

Default Value

''

Remarks

The current element is specified via the XPath property.

Config Method (XML Component)

Sets or retrieves a configuration setting.

Syntax

function Config(ConfigurationString: String): String;

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings 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, you must call Config("PROPERTY"). The value will be returned as a string.

EndElement Method (XML Component)

Writes the closing tag of an open XML element.

Syntax

procedure EndElement();

Remarks

Writes the closing tag of the XML element most recently opened using StartElement.

If no elements are opened, the call raises an exception

Flush Method (XML Component)

Flushes the parser and checks its end state.

Syntax

procedure Flush();

Remarks

When Flush is called, the parser flushes all its buffers, firing events as necessary, and then checks its end state. If Validate is true, the parser verifies that all open elements were closed, returning an error if not.

GetAttr Method (XML Component)

Returns the value of the specified attribute.

Syntax

function GetAttr(AttrName: String): String;

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 exit is controlled by ErrorOnEmptyAttr.

Please refer to the Name, Namespace, Prefix, and Value properties for more information.

HasXPath Method (XML Component)

Determines whether a specific element exists in the document.

Syntax

function HasXPath(XPath: String): Boolean;

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 via XPath.

This method returns True if the xpath exists, False if not.

See XPath for details on the XPath syntax.

LoadDOM Method (XML Component)

Loads the DOM from a file.

Syntax

procedure LoadDOM(FileName: String);

Remarks

The LoadDOM method loads a DOM structure previously saved by SaveDOM from the file specified in FileName.

Please refer to the SaveDOM method for more information.

LoadSchema Method (XML Component)

Load the XML schema.

Syntax

procedure LoadSchema(Schema: String);

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 it adheres to the schema.

Parse Method (XML Component)

This method parses the specified XML data.

Syntax

procedure Parse();

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 if BuildDOM is True (default). If BuildDOM is False parsed data is only accessible through the events.

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

If BuildDOM is True (default), XPath may be set after this method returns. XPath implements a subset of the XML XPath specification, allowing you to point to specific elements in the XML documents.

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 points to the name of the element, with XParent, XNamespace, XPrefix, Name, Namespace, Prefix, XText, and XText providing other properties of the element. The attributes of the current element are provided in the Name, Namespace, Prefix, and Value properties.

BuildDOM must be set to True prior to parsing the document for the XPath functionality to be available.

Example (Setting XPath):

Document rootXML.XPath = "/"
Specific ElementXML.XPath = "/root/SubElement1/SubElement2/"
i-th ChildXML.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:

When a valid source is found the search stops.

If parsing multiple documents call Reset between documents to reset the parser.

PutAttr Method (XML Component)

Writes an XML attribute.

Syntax

procedure PutAttr(Name: String; NamespaceURI: String; Value: String);

Remarks

Writes an XML attribute on the currently opened XML element. It must be called right after calling StartElement and before any calls to PutString, PutComment or PutRaw.

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, then 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.

PutCData Method (XML Component)

Writes an XML CDATA block.

Syntax

procedure PutCData(Text: String);

Remarks

Writes a new XML CDATA block with the specified text inside the current element.

PutComment Method (XML Component)

Writes an XML comment block.

Syntax

procedure PutComment(Text: String);

Remarks

Writes a new XML comment block with the specified text.

PutElement Method (XML Component)

Writes a simple XML element with a value.

Syntax

procedure PutElement(Name: String; NamespaceURI: String; Value: String);

Remarks

Writes a simple XML element with no attributes and the specified value between the opening and closing tags.

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, then component will automatically introduce a new xmlns:prefix="NamespaceURI" as necessary.

When calling PutElement 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:

<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 code: 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 the above 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 Component)

Writes a raw XML fragment.

Syntax

procedure PutRaw(Text: String);

Remarks

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 Component)

Writes text inside an XML element.

Syntax

procedure PutString(Text: String);

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 Component)

Remove a attribute.

Syntax

procedure RemoveAttr(AttrName: String);

Remarks

This method removes an attribute at the specified XPath

This functionality is not yet implemented.

RemoveChildren Method (XML Component)

Removes the children of the elment as the specified XPath.

Syntax

procedure RemoveChildren();

Remarks

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

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 returns, or from within the EndElement event as a document is parsed in order 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.

RemoveChildren Example:

Given the XML

<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.

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

The XML stored in the DOM is now:

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

RemoveElement Method (XML Component)

Removes the elment as the specified XPath.

Syntax

procedure RemoveElement();

Remarks

This method removes the element specified by XPath.

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 returns, or from within the EndElement event as a document is parsed in order 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.

RemoveElement Example:

Given the XML

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

This code removes the apple element and its children.

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

The XML stored in the DOM is now:

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

Reset Method (XML Component)

Resets the parser.

Syntax

procedure Reset();

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 signal to the parser that the current stream of text has terminated.

Save Method (XML Component)

Closes the component writing stream.

Syntax

procedure Save();

Remarks

This method will close any open XML elements, and then close the OutputFile if necessary.

SaveDOM Method (XML Component)

Saves the DOM to a file.

Syntax

procedure SaveDOM(FileName: String);

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 method for more information.

SetInputStream Method (XML Component)

Sets the stream from which the component will read data to parse.

Syntax

procedure SetInputStream(InputStream: TStream);

Remarks

This method specifies a stream from which data will be read when Parse 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:

When a valid source is found the search stops.

SetOutputStream Method (XML Component)

The stream to which the component will write the XML.

Syntax

procedure SetOutputStream(OutputStream: TStream);

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:

  • OutputFile
  • OutputData: The output data is written to this property if no other destination is specified.

StartElement Method (XML Component)

Writes the opening tag of an XML element.

Syntax

procedure StartElement(Name: String; NamespaceURI: String);

Remarks

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, then component will automatically introduce a new xmlns:prefix="NamespaceURI" as necessary.

When calling PutElement 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:

<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 code: 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 the above 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 Component)

Navigates to the specified XPath if it exists.

Syntax

function TryXPath(xpath: String): Boolean;

Remarks

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

If the XPath exists the XPath property will be updated and this method returns True.

If the XPath does not exist the XPath property is not updated and this method returns False.

Characters Event (XML Component)

Fired for plain text segments of the input stream.

Syntax

type TCharactersEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnCharacters: TCharactersEvent read FOnCharacters write FOnCharacters;

Remarks

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

The text includes white space as well as end of line characters, except for ignorable whitespace which is fired through the IgnorableWhitespace event.

Comment Event (XML Component)

Fired when a comment section is encountered.

Syntax

type TCommentEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnComment: TCommentEvent read FOnComment write FOnComment;

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 Component)

Fired when an end-element tag is encountered.

Syntax

type TEndElementEvent = procedure (
  Sender: TObject;
  const Namespace: String;
  const Element: String;
  const QName: String;
  IsEmpty: Boolean
) of Object;

property OnEndElement: TEndElementEvent read FOnEndElement write FOnEndElement;

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 with an empty element declaration.

EndPrefixMapping Event (XML Component)

Fired when leaving the scope of a namespace declaration.

Syntax

type TEndPrefixMappingEvent = procedure (
  Sender: TObject;
  const Prefix: String
) of Object;

property OnEndPrefixMapping: TEndPrefixMappingEvent read FOnEndPrefixMapping write FOnEndPrefixMapping;

Remarks

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

Error Event (XML Component)

Information about errors during data delivery.

Syntax

type TErrorEvent = procedure (
  Sender: TObject;
  ErrorCode: Integer;
  const Description: String
) of Object;

property OnError: TErrorEvent read FOnError write FOnError;

Remarks

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

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

EvalEntity Event (XML Component)

Fired every time an entity needs to be evaluated.

Syntax

type TEvalEntityEvent = procedure (
  Sender: TObject;
  const Entity: String;
  var Value: String
) of Object;

property OnEvalEntity: TEvalEntityEvent read FOnEvalEntity write FOnEvalEntity;

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 be later passed into the text stream.

IgnorableWhitespace Event (XML Component)

Fired when a section of ignorable whitespace is encountered.

Syntax

type TIgnorableWhitespaceEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnIgnorableWhitespace: TIgnorableWhitespaceEvent read FOnIgnorableWhitespace write FOnIgnorableWhitespace;

Remarks

The ignorable whitespace section is provided by the Text parameter.

Meta Event (XML Component)

Fired when a meta section is encountered.

Syntax

type TMetaEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnMeta: TMetaEvent read FOnMeta write FOnMeta;

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 Component)

Fired when a processing instruction section is encountered.

Syntax

type TPIEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnPI: TPIEvent read FOnPI write FOnPI;

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 Component)

Fired when a special section is encountered.

Syntax

type TSpecialSectionEvent = procedure (
  Sender: TObject;
  const SectionId: String;
  const Text: String
) of Object;

property OnSpecialSection: TSpecialSectionEvent read FOnSpecialSection write FOnSpecialSection;

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, while the SectionId parameter provides the section identifier (e.g. "CDATA").

StartElement Event (XML Component)

Fired when a begin-element tag is encountered in the document.

Syntax

type TStartElementEvent = procedure (
  Sender: TObject;
  const Namespace: String;
  const Element: String;
  const QName: String;
  IsEmpty: Boolean
) of Object;

property OnStartElement: TStartElementEvent read FOnStartElement write FOnStartElement;

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 Name, Namespace, Prefix, and Value properties.

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

StartPrefixMapping Event (XML Component)

Fired when entering the scope of a namespace declaration.

Syntax

type TStartPrefixMappingEvent = procedure (
  Sender: TObject;
  const Prefix: String;
  const URI: String
) of Object;

property OnStartPrefixMapping: TStartPrefixMappingEvent read FOnStartPrefixMapping write FOnStartPrefixMapping;

Remarks

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

XML Event (XML Component)

Fires as XML is written.

Syntax

type TXMLEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnXML: TXMLEvent read FOnXML write FOnXML;

Remarks

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

This functionality is not yet implemented.

XMLAttribute Type

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.

Fields

Name
String

The Name provides the local name (without prefix) of the attribute.

Namespace
String

Attribute namespace.

Prefix
String

Attribute prefix (if any). If the attribute does not have a prefix, this property is empty.

Value
String

Attribute value.

Constructors

constructor Create();

XMLComment Type

A comment within the document.

Remarks

This type holds a comment within the XML document.

Fields

Text
String

This property holds the comment text.

Constructors

constructor Create();
constructor Create(valText: String);

XMLDeclaration Type

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 only applicable when writing documents.

Fields

Encoding
String

This property specifies the XML encoding to use.

This may be set before writing a document. The default value is "utf-8".

This is only applicable when writing XML.

Standalone
Boolean

This property 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 only applicable when writing XML.

Version
String

This property specifies the XML version.

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

This is only applicable when writing XML.

Constructors

constructor Create();
constructor Create(valVersion: String; valEncoding: String; valStandalone: Boolean);

XMLElement Type

An element contained within the XML document.

Remarks

This type describes an XML element. The fields for this type describe the element Name, Prefix, and Namespace of the given element.

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

Fields

Name
String

The Name property provides the local name (without prefix) of the element.

Namespace
String

Namespace of the element.

Prefix
String

Prefix of the element (if any). If the element does not have a prefix, this property is empty.

XText
String

The inner text of the element.

Constructors

constructor Create();

XMLNamespace Type

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 and the URI of the namespace being defined.

The default namespace exists at index 0. The Prefix field at index 0 is "xmlns", and the Name field contains the default namespace.

Fields

Prefix
String

The Prefix for the Namespace.

URI
String

Namespace URI associated with the corresponding Prefix. This is usually a URL pointing to the XML schema for the namespace.

Constructors

constructor Create();

Configuration Settings (XML 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 method.

XML Configuration Settings

CacheContent:   If true, the original XML is saved in a buffer.

This config 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 setting specifies the character set used when encoding data. This value will also be used when creating the XMLDeclaration. The default value is "utf-8".

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 ('#13#10') .

This option should be combined with Indent for full effect.

ErrorOnEmptyAttr:   If true, passing an invalid attribute to the Attr method will throw an exception.

If an invalid attribute name is passed into the GetAttr method, the method will return with 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', 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 white space.

Normally, the parser considers only the following characters as white space: ' ' (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 white space, 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 property controls whether Characters events are fired for every line of the input text stream or not. Normally lines are buffered internally and delivered in batches, but if the FlushOnEOL flag is set, then a Characters 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 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 setting suppresses the error. The default value is True.

IncludeElementPrefix:   Whether to include the prefix in the element name.

This setting specifies whether to include the element prefix in the Element parameter of the StartElement and EndElement events.

If False (default) and Validate is set to False the prefix is included in the Element parameter. For instance: ds:DigestMethod

If True and Validate is set to False the prefix is not included in the Element parameter. For instance: DigestMethod

This setting is only applicable when Validate is False.

IncludeXMLDeclaration:   Whether to include the XML declaration when writing XML.

This 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:

<?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 for full effect.

Offset:   Current offset of the document being parsed.

This property is useful for determining the location of possible XML errors in the document.

Offset values start at 1.

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.

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 setting determines what additional processing is performed on string values fired through the Characters event..

Note: This only applies when BuildDOM 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:

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 event:

&amp;&quot;&lt;&gt;

When set to 1 the following text would be fired through the Characters event:

&'<>

Base Configuration Settings

BuildInfo:   Information about the product's build.

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

CodePage:   The system code page used for Unicode to Multibyte translations.

The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8

The following is a list of valid code page identifiers for Mac OS only:

IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary

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).
UseInternalSecurityAPI:   Tells the component whether or not to use the system security libraries or an internal implementation.

By default the component will use the system security libraries to perform cryptographic functions. Setting this to True tells the component to use the internal implementation instead of using the system's security API.

Trappable Errors (XML 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 (can't find namespace).
203   Unknown attribute prefix (can't find namespace).
204   Invalid XML markup.
205   Invalid end state for parser.
206   Document contains unbalanced elements.
207   Invalid XPath.
208   No such child.
209   Top element does not match start of path.
210   DOM tree unavailable (set BuildDOM to true and reparse).
302   Can't open file.
401   Invalid XML would be generated.
402   An invalid XML name has been specified.

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IPWorks 2022 Delphi Edition - Version 22.0 [Build 8171]