JSON Component

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The JSON component can be used to parse and write JSON documents.

Syntax

nsoftware.IPWorksMQ.JSON

Remarks

The JSON component offers a fast and simple way to parse and write information in JSON documents.

Parsing JSON

The JSON component parses JSON documents and verifies that they are well-formed. The results are provided through a set of events.

In addition, the document structure may be queried through an XPath mechanism that supports a subset of the XPath and JSONPath 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 that 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, it may be navigated by setting XPath if BuildDOM is True (default). If BuildDOM is False, parsed data are accessible only through the events.

The following events will fire during parsing:

If BuildDOM is True (default), XPath may be set after this method returns. XPath may be set to navigate to specific elements within the JSON document. This will be the path to a specified value within the document. Because arrays in JSON only contain values, and no associated object name, an empty name will be used for these values. To reach an array element at position 1, the path must be set to "[1]". In addition, a root element named "json" will be added to each JSON document in the parser.

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

The XPath property accepts both XPath and JSONPath formats. Please review the following notes on both formats.

XPath

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.
[i]The i-th subelement of the current element.
..the parent of the current element.
When XPath is set to a valid path, the following properties are updated:

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

Simple JSON Document

{
  "firstlevel": {
    "one": "value",
    "two": ["first", "second"],
    "three": "value three"
  }
}
Example 1. Setting XPath:

Document root JsonControl.XPath = "/"
Specific Element JsonControl.XPath = "/json/firstlevel/one/"
i-th Child JsonControl.XPath = "/json/firstlevel/two/[i]/"
Note: When using XPath notation, the root element is always referred to as "json". As in the previous examples, this means all paths will begin with "/json".

JSONPath

This property implements a subset of the JSONPath notation. This may be set to point to a specific element in the JSON document.

The JSONPath is a series of one or more accessors in either dot-notation 

$.store.book[0].title
or in bracket-notation, as follows: 
$['store']['book'][0]['title']

After setting XPath, the following properties are populated:

Example 2. Setting JSONPath:

Given the following JSON document: 

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
}
The following code shows several examples.

Get the first book's author:

json.XPath = "$.store.book[0].author"; Console.WriteLine(json.XText); //Output //"Nigel Rees" Select the first book and inspect the children:

json.XPath = "$.store.book[0]"; Console.WriteLine("Child Count: " + json.XChildren.Count); Console.WriteLine(json.XChildren[1].Name + ": " + json.XChildren[1].XText); //Output //Child Count: 4 //author: "Nigel Rees" Get the price of the second book:

json.XPath = "$['store']['book'][1]['price']"; Console.WriteLine(json.XText); //Output //12.99 Get the second to last book's author:

json.XPath = "$['store']['book'][last() - 1]['author']"; Console.WriteLine(json.XText); Console.WriteLine(json.XPath); //Note that "last() - 1" is resolved to "3". //Output //"Herman Melville" //$['store']['book'][3]['author'] Display the full subtree at the current path:

json.XPath = "$.store.book[0]"; Console.WriteLine(json.XSubTree); //Output // { // "category": "reference", // "author": "Nigel Rees", // "title": "Sayings of the Century", // "price": 8.95 // }

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.

Writing JSON

The JSON component also can be used to create a JSON document.

The document is written to the selected output property. In addition, as the document is written, the JSON event will fire. The Text event parameter contains the part of the document currently being written.

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:

Example. Writing a JSON Document:

Writing a simple JSON document describing a pet: Json json = new Json(); json.OutputFile = "C:\\temp\\fido.json"; json.StartObject(); json.PutProperty("name", "fido", 2); json.PutName("previousOwners"); json.StartArray(); json.PutValue("Steve Widgetson", 2); json.PutValue("Wanda Widgetson", 2); json.PutValue("Randy Cooper", 2); json.PutValue("Linda Glover", 2); json.EndArray(); json.PutProperty("weightUnit", "lbs", 2); json.PutProperty("weight", "62", 3); json.EndObject(); json.Flush();

This example results in the following JSON: 

{
  "name": "fido",
  "previousOwners": [
    "Steve Widgetson",
    "Wanda Widgetson",
    "Randy Cooper",
    "Linda Glover"
  ],
  "weightUnit": "lbs",
  "weight": 62
}

When writing multiple documents, call Reset between documents to reset the writer.

Modifying JSON

The JSON component also allows for modifying existing JSON documents. After loading a JSON document with Parse the document may be edited. The component supports inserting new values, renaming or overwriting existing values, and removing values. After editing is complete, call Save to output the updated JSON document.

The following methods are applicable when modifying a JSON document:

When Save is called, the modified JSON is written to the specified output location.

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:

Example 1. Inserting New Values:

To insert new values in a JSON document, first load the existing document with Parse. Next set XPath to the sibling or parent of the data to be inserted. Call InsertProperty or InsertValue and pass the ValueType and Position parameters to indicate the type of data being inserted and the position.

The ValueType parameter of these methods specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter of these methods specifies the position of Value. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

For example:

Given the following JSON: 

{
    "store": {
        "books": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
            }
        ]    
    }
}

Insert a new property "price" for each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("price", "8.95", 3, 3); //3 - Number, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("price", "12.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    }
    ]
  }
}

To add a new book to the array:

json.XPath = "/json/store/books"; json.InsertValue("", 0, 3); //0 - Object, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("category", "fiction", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("author", "Herman Melville", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("title", "Moby Dick", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("price", "8.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To add a new array property to each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[1]/tags"; json.InsertValue("quotes", 2, 3); //2 - String, 3 - Last Child json.InsertValue("british", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[2]/tags"; json.InsertValue("trilogy", 2, 3); //2 - String, 3 - Last Child json.InsertValue("war", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[3]/tags"; json.InsertValue("classic", 2, 3); //2 - String, 3 - Last Child json.InsertValue("whales", 2, 3); //2 - String, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["quotes", "british"],
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 2. Removing Values:

To remove existing values, set XPath and call the Remove method. Continuing with example 1, to remove the first book: json.XPath = "/json/store/books/[1]"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To remove the "category" properties from each book: json.XPath = "/json/store/books/[1]/category"; json.Remove(); json.XPath = "/json/store/books/[2]/category"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 3. Updating Existing Names and Values:

The SetName and SetValue methods may be used to modify existing names and values. Continuing with the preceding JSON in example 2, to rename "tags" to "meta" and update values within the array and prices:

//Rename "tags" to "meta" for 1st book json.XPath = "/json/store/books/[1]/tags"; json.SetName("meta"); //Update Price json.XPath = "/json/store/books/[1]/price"; json.SetValue("13.99", 3); //3 - Number //Rename "tags" to "meta" for 2nd book json.XPath = "/json/store/books/[2]/tags"; json.SetName("meta"); //Update tag "whales" to "revenge" json.XPath = "/json/store/books/[2]/meta/[2]"; json.SetValue("revenge", 2); //2 - String //Update Price json.XPath = "/json/store/books/[2]/price"; json.SetValue("9.99", 3); //3 - Number json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "meta": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 13.99
    },
    {
      "meta": ["classic", "revenge"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 9.99
    }
    ]
  }
}

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 JSON document is created.
InputDataThis property includes the JSON data to parse.
InputFileThis property specifies the file to process.
OutputDataThis property includes the output JSON after processing.
OutputFileThis is the path to a local file where the output will be written.
OverwriteThis property indicates whether or not the component should overwrite files.
ValidateThis property controls whether documents are validated during parsing.
XChildrenThis property includes a collection of child elements of the current element.
XElementThis property includes the name of the current element.
XElementTypeThis property indicates the data type of the current element.
XErrorPathThis property includes an XPath to check the server response for errors.
XParentThe parent of the current element.
XPathThis property provides a way to point to a specific element in the response.
XSubTreeThis property includes a snapshot of the current element in the document.
XTextThis 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.

ConfigSets or retrieves a configuration setting.
EndArrayThis method writes the closing bracket of a JSON array.
EndObjectThis method writes the closing brace of a JSON object.
FlushThis method flushes the parser's or writer's buffers.
HasXPathThis method determines whether a specific element exists in the document.
InsertPropertyThis method inserts the specified name and value at the selected position.
InsertValueThis method inserts the specified value at the selected position.
ParseThis method parses the specified JSON data.
PutNameThis method writes the name of a property.
PutPropertyThis method writes a property and value.
PutRawThis method writes a raw JSON fragment.
PutValueThis method writes a value of a property.
RemoveThis method removes the element or value set in XPath.
ResetThis method resets the component
SaveThis method saves the modified JSON document.
SetInputStreamThis method sets the stream from which the component will read data to parse.
SetNameThis method sets a new name for the element specified by XPath.
SetOutputStreamThis method sets the stream to which the component will write the JSON.
SetValueThis method sets a new value for the element specified by XPath.
StartArrayThis method writes the opening bracket of a JSON array.
StartObjectThis event writes the opening brace of a JSON object.
TryXPathThis 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.

CharactersThis event is fired for plaintext segments of the input stream.
EndDocumentThis event fires when the end of a JSON document is encountered.
EndElementThis event is fired when an end-element tag is encountered.
ErrorFired when information is available about errors during data delivery.
IgnorableWhitespaceThis event is fired when a section of ignorable whitespace is encountered.
JSONThis event fires with the JSON data being written.
StartDocumentThis event fires when the start of a new JSON document is encountered.
StartElementThis event is fired when a new element is encountered in the document.

Config Settings

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

CacheContentIf true, the original JSON is stored internally in a buffer.
CharsetSpecifies the charset used when encoding data.
CloseInputStreamAfterProcessDetermines whether or not the input stream is closed after processing.
CloseOutputStreamAfterProcessDetermines whether or not the output stream is closed after processing.
ElementXPathThe XPath value for the current element in the document.
EscapeForwardSlashesWhether to escape forward slashes when writing a JSON object.
InputFormatSpecifies the input format used in JSON streaming.
PrettyPrintDetermines whether output is on one line or "pretty printed".
RecordEndDelimiterThe character sequence after the end of a JSON document.
RecordStartDelimiterThe character sequence before the start of a JSON document.
StringProcessingOptionsDefines options to use when processing string values.
XPathNotationSpecifies the expected format when setting XPath.

BuildDOM Property (JSON Component)

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

Syntax

public bool BuildDOM { get; set; }

Public Property BuildDOM As Boolean

Default Value

True

Remarks

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

InputData Property (JSON Component)

This property includes the JSON data to parse.

Syntax

public string InputData { get; set; }

Public Property InputData As String

Default Value

""

Remarks

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

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

//Parse the following in chunks: { "data": 1} json.InputData = "{ \"data\"" json.Parse(); json.InputData = ": 1}" json.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 (JSON Component)

This property specifies the file to process.

Syntax

public string InputFile { get; set; }

Public Property InputFile As String

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 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.

OutputData Property (JSON Component)

This property includes the output JSON after processing.

Syntax

public string OutputData { get; set; }

Public Property OutputData As String

Default Value

""

Remarks

This property contains the resultant JSON after processing.

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 Property (JSON Component)

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

Syntax

public string OutputFile { get; set; }

Public Property OutputFile As String

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:

Overwrite Property (JSON Component)

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

Syntax

public bool Overwrite { get; set; }

Public Property Overwrite As Boolean

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 (JSON Component)

This property controls whether documents are validated during parsing.

Syntax

public bool Validate { get; set; }

Public Property Validate As Boolean

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.

XChildren Property (JSON Component)

This property includes a collection of child elements of the current element.

Syntax

public JSONElementList XChildren { get; }

Public Property XChildren As JSONElementList

Remarks

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

This collection is indexed from 0 to count -1.

This property is not available at design time.

Please refer to the JSONElement type for a complete list of fields.

XElement Property (JSON Component)

This property includes the name of the current element.

Syntax

public string XElement { get; set; }

Public Property XElement As String

Default Value

""

Remarks

This property contains the name of the current element. The current element is specified through the XPath property.

XElementType Property (JSON Component)

This property indicates the data type of the current element.

Syntax

public JSONXElementTypes XElementType { get; }

enum JSONXElementTypes {
  etObject,
  etArray,
  etString,
  etNumber,
  etBool,
  etNull
}

Public ReadOnly Property XElementType As JsonXElementTypes

Enum JSONXElementTypes
  etObject
  etArray
  etString
  etNumber
  etBool
  etNull
End Enum

Default Value

0

Remarks

This property specifies the data type of the current element. After setting XPath, this property is populated. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

Note: This property is not applicable when parsing a document and BuildDOM is False.

This property is read-only.

XErrorPath Property (JSON Component)

This property includes an XPath to check the server response for errors.

Syntax

public string XErrorPath { get; set; }

Public Property XErrorPath As String

Default Value

""

Remarks

This property contains an XPath to check the server response for errors. If the XPath exists, an exception will be thrown containing the value of the element at the path.

XParent Property (JSON Component)

The parent of the current element.

Syntax

public string XParent { get; }

Public ReadOnly Property XParent As String

Default Value

""

Remarks

This property contains the parent of the current element. The current element is specified via the XPath property.

This property is read-only.

XPath Property (JSON Component)

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

Syntax

public string XPath { get; set; }

Public Property XPath As String

Default Value

""

Remarks

XPath may be set to navigate to specific elements within the JSON document. This will be the path to a specified value within the document. Because arrays in JSON only contain values, and no associated object name, an empty name will be used for these values. To reach an array element at position 1, the path must be set to "[1]". In addition, a root element named "json" will be added to each JSON document in the parser.

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

The XPath property accepts both XPath and JSONPath formats. Please review the following notes on both formats.

XPath

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.
[i]The i-th subelement of the current element.
..the parent of the current element.
When XPath is set to a valid path, the following properties are updated:

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

Simple JSON Document

{
  "firstlevel": {
    "one": "value",
    "two": ["first", "second"],
    "three": "value three"
  }
}
Example 1. Setting XPath:

Document root JsonControl.XPath = "/"
Specific Element JsonControl.XPath = "/json/firstlevel/one/"
i-th Child JsonControl.XPath = "/json/firstlevel/two/[i]/"
Note: When using XPath notation, the root element is always referred to as "json". As in the previous examples, this means all paths will begin with "/json".

JSONPath

This property implements a subset of the JSONPath notation. This may be set to point to a specific element in the JSON document.

The JSONPath is a series of one or more accessors in either dot-notation 

$.store.book[0].title
or in bracket-notation, as follows: 
$['store']['book'][0]['title']

After setting XPath, the following properties are populated:

Example 2. Setting JSONPath:

Given the following JSON document: 

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
}
The following code shows several examples.

Get the first book's author:

json.XPath = "$.store.book[0].author"; Console.WriteLine(json.XText); //Output //"Nigel Rees" Select the first book and inspect the children:

json.XPath = "$.store.book[0]"; Console.WriteLine("Child Count: " + json.XChildren.Count); Console.WriteLine(json.XChildren[1].Name + ": " + json.XChildren[1].XText); //Output //Child Count: 4 //author: "Nigel Rees" Get the price of the second book:

json.XPath = "$['store']['book'][1]['price']"; Console.WriteLine(json.XText); //Output //12.99 Get the second to last book's author:

json.XPath = "$['store']['book'][last() - 1]['author']"; Console.WriteLine(json.XText); Console.WriteLine(json.XPath); //Note that "last() - 1" is resolved to "3". //Output //"Herman Melville" //$['store']['book'][3]['author'] Display the full subtree at the current path:

json.XPath = "$.store.book[0]"; Console.WriteLine(json.XSubTree); //Output // { // "category": "reference", // "author": "Nigel Rees", // "title": "Sayings of the Century", // "price": 8.95 // }

XSubTree Property (JSON Component)

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

Syntax

public string XSubTree { get; }

Public ReadOnly Property XSubTree As String

Default Value

""

Remarks

The current element is specified through this property. For this property to work, you must have the CacheContent set to True.

This property is read-only.

XText Property (JSON Component)

This property includes the text of the current element.

Syntax

public string XText { get; set; }

Public Property XText As String

Default Value

""

Remarks

This property contains the text of the current element. The current element is specified through the XPath property.

Config Method (JSON Component)

Sets or retrieves a configuration setting.

Syntax

public string Config(string configurationString);

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

Public Function Config(ByVal ConfigurationString As String) As String

Async Version
Public Function Config(ByVal ConfigurationString As String) As Task(Of String)
Public Function Config(ByVal ConfigurationString As String, cancellationToken As CancellationToken) As Task(Of 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.

EndArray Method (JSON Component)

This method writes the closing bracket of a JSON array.

Syntax

public void EndArray();

Async Version
public async Task EndArray();
public async Task EndArray(CancellationToken cancellationToken);

Public Sub EndArray()

Async Version
Public Sub EndArray() As Task
Public Sub EndArray(cancellationToken As CancellationToken) As Task

Remarks

This method writes the closing bracket of a JSON array to the output. An array must already have been opened by calling StartArray.

EndObject Method (JSON Component)

This method writes the closing brace of a JSON object.

Syntax

public void EndObject();

Async Version
public async Task EndObject();
public async Task EndObject(CancellationToken cancellationToken);

Public Sub EndObject()

Async Version
Public Sub EndObject() As Task
Public Sub EndObject(cancellationToken As CancellationToken) As Task

Remarks

This method writes the closing brace of a JSON object. An object must have been started previously by calling StartObject.

Flush Method (JSON Component)

This method flushes the parser's or writer's buffers.

Syntax

public void Flush();

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

Public Sub Flush()

Async Version
Public Sub Flush() As Task
Public Sub Flush(cancellationToken As CancellationToken) As Task

Remarks

When Flush is called, the component flushes all of its buffers, firing events as necessary.

When parsing, the end state of the JSON is checked. If Validate is also True, the parser verifies that all open elements were closed, returning an error if not.

When writing, the resultant JSON is available in one of the output properties.

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:

HasXPath Method (JSON Component)

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

Syntax

public bool HasXPath(string XPath);

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

Public Function HasXPath(ByVal XPath As String) As Boolean

Async Version
Public Function HasXPath(ByVal XPath As String) As Task(Of Boolean)
Public Function HasXPath(ByVal XPath As String, cancellationToken As CancellationToken) As Task(Of 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 through XPath.

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

See XPath for details on the XPath syntax.

InsertProperty Method (JSON Component)

This method inserts the specified name and value at the selected position.

Syntax

public void InsertProperty(string name, string value, int valueType, int position);

Async Version
public async Task InsertProperty(string name, string value, int valueType, int position);
public async Task InsertProperty(string name, string value, int valueType, int position, CancellationToken cancellationToken);

Public Sub InsertProperty(ByVal Name As String, ByVal Value As String, ByVal ValueType As Integer, ByVal Position As Integer)

Async Version
Public Sub InsertProperty(ByVal Name As String, ByVal Value As String, ByVal ValueType As Integer, ByVal Position As Integer) As Task
Public Sub InsertProperty(ByVal Name As String, ByVal Value As String, ByVal ValueType As Integer, ByVal Position As Integer, cancellationToken As CancellationToken) As Task

Remarks

This method inserts a property and its corresponding value relative to the element specified by XPath. Before calling this method, a valid JSON document must first be loaded by calling Parse.

The Name parameter specifies the name of the property.

The Value parameter specifies the value of the property.

The ValueType parameter specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter specifies the position of Value relative to the element specified by XPath. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

See Save for details.

InsertValue Method (JSON Component)

This method inserts the specified value at the selected position.

Syntax

public void InsertValue(string value, int valueType, int position);

Async Version
public async Task InsertValue(string value, int valueType, int position);
public async Task InsertValue(string value, int valueType, int position, CancellationToken cancellationToken);

Public Sub InsertValue(ByVal Value As String, ByVal ValueType As Integer, ByVal Position As Integer)

Async Version
Public Sub InsertValue(ByVal Value As String, ByVal ValueType As Integer, ByVal Position As Integer) As Task
Public Sub InsertValue(ByVal Value As String, ByVal ValueType As Integer, ByVal Position As Integer, cancellationToken As CancellationToken) As Task

Remarks

This method inserts a value relative to the element specified by XPath. Before calling this method, a valid JSON document must first be loaded by calling Parse.

The Value parameter specifies the value of the property.

The ValueType parameter specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter specifies the position of Value relative to the element specified by XPath. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

See Save for details.

Parse Method (JSON Component)

This method parses the specified JSON data.

Syntax

public void Parse();

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

Public Sub Parse()

Async Version
Public Sub Parse() As Task
Public Sub Parse(cancellationToken As CancellationToken) As Task

Remarks

This method parses the specified JSON data.

When parsing a document, events will fire to provide information about the parsed data. After Parse returns the document, it may be navigated by setting XPath if BuildDOM is True (default). If BuildDOM is False, parsed data are accessible only through the events.

The following events will fire during parsing:

If BuildDOM is True (default), XPath may be set after this method returns. XPath may be set to navigate to specific elements within the JSON document. This will be the path to a specified value within the document. Because arrays in JSON only contain values, and no associated object name, an empty name will be used for these values. To reach an array element at position 1, the path must be set to "[1]". In addition, a root element named "json" will be added to each JSON document in the parser.

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

The XPath property accepts both XPath and JSONPath formats. Please review the following notes on both formats.

XPath

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.
[i]The i-th subelement of the current element.
..the parent of the current element.
When XPath is set to a valid path, the following properties are updated:

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

Simple JSON Document

{
  "firstlevel": {
    "one": "value",
    "two": ["first", "second"],
    "three": "value three"
  }
}
Example 1. Setting XPath:

Document root JsonControl.XPath = "/"
Specific Element JsonControl.XPath = "/json/firstlevel/one/"
i-th Child JsonControl.XPath = "/json/firstlevel/two/[i]/"
Note: When using XPath notation, the root element is always referred to as "json". As in the previous examples, this means all paths will begin with "/json".

JSONPath

This property implements a subset of the JSONPath notation. This may be set to point to a specific element in the JSON document.

The JSONPath is a series of one or more accessors in either dot-notation 

$.store.book[0].title
or in bracket-notation, as follows: 
$['store']['book'][0]['title']

After setting XPath, the following properties are populated:

Example 2. Setting JSONPath:

Given the following JSON document: 

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
}
The following code shows several examples.

Get the first book's author:

json.XPath = "$.store.book[0].author"; Console.WriteLine(json.XText); //Output //"Nigel Rees" Select the first book and inspect the children:

json.XPath = "$.store.book[0]"; Console.WriteLine("Child Count: " + json.XChildren.Count); Console.WriteLine(json.XChildren[1].Name + ": " + json.XChildren[1].XText); //Output //Child Count: 4 //author: "Nigel Rees" Get the price of the second book:

json.XPath = "$['store']['book'][1]['price']"; Console.WriteLine(json.XText); //Output //12.99 Get the second to last book's author:

json.XPath = "$['store']['book'][last() - 1]['author']"; Console.WriteLine(json.XText); Console.WriteLine(json.XPath); //Note that "last() - 1" is resolved to "3". //Output //"Herman Melville" //$['store']['book'][3]['author'] Display the full subtree at the current path:

json.XPath = "$.store.book[0]"; Console.WriteLine(json.XSubTree); //Output // { // "category": "reference", // "author": "Nigel Rees", // "title": "Sayings of the Century", // "price": 8.95 // }

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.

PutName Method (JSON Component)

This method writes the name of a property.

Syntax

public void PutName(string name);

Async Version
public async Task PutName(string name);
public async Task PutName(string name, CancellationToken cancellationToken);

Public Sub PutName(ByVal Name As String)

Async Version
Public Sub PutName(ByVal Name As String) As Task
Public Sub PutName(ByVal Name As String, cancellationToken As CancellationToken) As Task

Remarks

This method writes the name of a property. The Name parameter specifies the value to write.

PutProperty Method (JSON Component)

This method writes a property and value.

Syntax

public void PutProperty(string name, string value, int valueType);

Async Version
public async Task PutProperty(string name, string value, int valueType);
public async Task PutProperty(string name, string value, int valueType, CancellationToken cancellationToken);

Public Sub PutProperty(ByVal Name As String, ByVal Value As String, ByVal ValueType As Integer)

Async Version
Public Sub PutProperty(ByVal Name As String, ByVal Value As String, ByVal ValueType As Integer) As Task
Public Sub PutProperty(ByVal Name As String, ByVal Value As String, ByVal ValueType As Integer, cancellationToken As CancellationToken) As Task

Remarks

This method writes a property and its corresponding value to the output.

The Name parameter specifies the name of the property.

The Value parameter specifies the value of the property.

The ValueType parameter specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

PutRaw Method (JSON Component)

This method writes a raw JSON fragment.

Syntax

public void PutRaw(string text);

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

Public Sub PutRaw(ByVal Text As String)

Async Version
Public Sub PutRaw(ByVal Text As String) As Task
Public Sub PutRaw(ByVal Text As String, cancellationToken As CancellationToken) As Task

Remarks

This method writes raw data to the output. This may be used to write any data of any format directly to the output.

PutValue Method (JSON Component)

This method writes a value of a property.

Syntax

public void PutValue(string value, int valueType);

Async Version
public async Task PutValue(string value, int valueType);
public async Task PutValue(string value, int valueType, CancellationToken cancellationToken);

Public Sub PutValue(ByVal Value As String, ByVal ValueType As Integer)

Async Version
Public Sub PutValue(ByVal Value As String, ByVal ValueType As Integer) As Task
Public Sub PutValue(ByVal Value As String, ByVal ValueType As Integer, cancellationToken As CancellationToken) As Task

Remarks

This method writes the value of a property to the output. The Value parameter specifies the value. The ValueType parameter specifies the type of data. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

Remove Method (JSON Component)

This method removes the element or value set in XPath.

Syntax

public void Remove();

Async Version
public async Task Remove();
public async Task Remove(CancellationToken cancellationToken);

Public Sub Remove()

Async Version
Public Sub Remove() As Task
Public Sub Remove(cancellationToken As CancellationToken) As Task

Remarks

This method removes the current object at the specified XPath. This is used when editing previously loaded JSON documents.

See Save for details.

Reset Method (JSON Component)

This method resets the component

Syntax

public void Reset();

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

Public Sub Reset()

Async Version
Public Sub Reset() As Task
Public Sub Reset(cancellationToken As CancellationToken) As Task

Remarks

This method resets the JSON parser.

Save Method (JSON Component)

This method saves the modified JSON document.

Syntax

public void Save();

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

Public Sub Save()

Async Version
Public Sub Save() As Task
Public Sub Save(cancellationToken As CancellationToken) As Task

Remarks

This method saves the modified JSON data. This is used after editing a previously loaded JSON document.

After loading a JSON document with Parse the document may be edited. The component supports inserting new values, renaming or overwriting existing values, and removing values. After editing is complete, call Save to output the updated JSON document.

The following methods are applicable when modifying a JSON document:

When Save is called, the modified JSON is written to the specified output location.

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:

Example 1. Inserting New Values:

To insert new values in a JSON document, first load the existing document with Parse. Next set XPath to the sibling or parent of the data to be inserted. Call InsertProperty or InsertValue and pass the ValueType and Position parameters to indicate the type of data being inserted and the position.

The ValueType parameter of these methods specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter of these methods specifies the position of Value. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

For example:

Given the following JSON: 

{
    "store": {
        "books": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
            }
        ]    
    }
}

Insert a new property "price" for each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("price", "8.95", 3, 3); //3 - Number, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("price", "12.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    }
    ]
  }
}

To add a new book to the array:

json.XPath = "/json/store/books"; json.InsertValue("", 0, 3); //0 - Object, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("category", "fiction", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("author", "Herman Melville", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("title", "Moby Dick", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("price", "8.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To add a new array property to each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[1]/tags"; json.InsertValue("quotes", 2, 3); //2 - String, 3 - Last Child json.InsertValue("british", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[2]/tags"; json.InsertValue("trilogy", 2, 3); //2 - String, 3 - Last Child json.InsertValue("war", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[3]/tags"; json.InsertValue("classic", 2, 3); //2 - String, 3 - Last Child json.InsertValue("whales", 2, 3); //2 - String, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["quotes", "british"],
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 2. Removing Values:

To remove existing values, set XPath and call the Remove method. Continuing with example 1, to remove the first book: json.XPath = "/json/store/books/[1]"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To remove the "category" properties from each book: json.XPath = "/json/store/books/[1]/category"; json.Remove(); json.XPath = "/json/store/books/[2]/category"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 3. Updating Existing Names and Values:

The SetName and SetValue methods may be used to modify existing names and values. Continuing with the preceding JSON in example 2, to rename "tags" to "meta" and update values within the array and prices:

//Rename "tags" to "meta" for 1st book json.XPath = "/json/store/books/[1]/tags"; json.SetName("meta"); //Update Price json.XPath = "/json/store/books/[1]/price"; json.SetValue("13.99", 3); //3 - Number //Rename "tags" to "meta" for 2nd book json.XPath = "/json/store/books/[2]/tags"; json.SetName("meta"); //Update tag "whales" to "revenge" json.XPath = "/json/store/books/[2]/meta/[2]"; json.SetValue("revenge", 2); //2 - String //Update Price json.XPath = "/json/store/books/[2]/price"; json.SetValue("9.99", 3); //3 - Number json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "meta": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 13.99
    },
    {
      "meta": ["classic", "revenge"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 9.99
    }
    ]
  }
}

SetInputStream Method (JSON Component)

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

Syntax

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);

Public Sub SetInputStream(ByVal InputStream As System.IO.Stream)

Async Version
Public Sub SetInputStream(ByVal InputStream As System.IO.Stream) As Task
Public Sub SetInputStream(ByVal InputStream As System.IO.Stream, cancellationToken As CancellationToken) As Task

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.

SetName Method (JSON Component)

This method sets a new name for the element specified by XPath.

Syntax

public void SetName(string name);

Async Version
public async Task SetName(string name);
public async Task SetName(string name, CancellationToken cancellationToken);

Public Sub SetName(ByVal Name As String)

Async Version
Public Sub SetName(ByVal Name As String) As Task
Public Sub SetName(ByVal Name As String, cancellationToken As CancellationToken) As Task

Remarks

This method sets a new name for the element specified in XPath. This is used to modify an existing JSON document.

The Name parameter specifies the new name of the element.

See Save for details.

SetOutputStream Method (JSON Component)

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

Syntax

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);

Public Sub SetOutputStream(ByVal OutputStream As System.IO.Stream)

Async Version
Public Sub SetOutputStream(ByVal OutputStream As System.IO.Stream) As Task
Public Sub SetOutputStream(ByVal OutputStream As System.IO.Stream, cancellationToken As CancellationToken) As Task

Remarks

This method sets the stream to which the 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
  • OutputData: The output data are written to this property if no other destination is specified.

SetValue Method (JSON Component)

This method sets a new value for the element specified by XPath.

Syntax

public void SetValue(string value, int valueType);

Async Version
public async Task SetValue(string value, int valueType);
public async Task SetValue(string value, int valueType, CancellationToken cancellationToken);

Public Sub SetValue(ByVal Value As String, ByVal ValueType As Integer)

Async Version
Public Sub SetValue(ByVal Value As String, ByVal ValueType As Integer) As Task
Public Sub SetValue(ByVal Value As String, ByVal ValueType As Integer, cancellationToken As CancellationToken) As Task

Remarks

This method sets a new value for the element specified in XPath. This is used to modify an existing JSON document.

Value specifies the new value.

ValueType specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

See Save for details.

StartArray Method (JSON Component)

This method writes the opening bracket of a JSON array.

Syntax

public void StartArray();

Async Version
public async Task StartArray();
public async Task StartArray(CancellationToken cancellationToken);

Public Sub StartArray()

Async Version
Public Sub StartArray() As Task
Public Sub StartArray(cancellationToken As CancellationToken) As Task

Remarks

This method writes the opening bracket of a JSON array to the output. To close the array, call EndArray.

StartObject Method (JSON Component)

This event writes the opening brace of a JSON object.

Syntax

public void StartObject();

Async Version
public async Task StartObject();
public async Task StartObject(CancellationToken cancellationToken);

Public Sub StartObject()

Async Version
Public Sub StartObject() As Task
Public Sub StartObject(cancellationToken As CancellationToken) As Task

Remarks

This method writes the opening brace of a JSON object to the output. To close the object, call EndObject.

TryXPath Method (JSON Component)

This method navigates to the specified XPath if it exists.

Syntax

public bool TryXPath(string xpath);

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

Public Function TryXPath(ByVal xpath As String) As Boolean

Async Version
Public Function TryXPath(ByVal xpath As String) As Task(Of Boolean)
Public Function TryXPath(ByVal xpath As String, cancellationToken As CancellationToken) As Task(Of 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 (JSON Component)

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

Syntax

public event OnCharactersHandler OnCharacters;

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

public class JSONCharactersEventArgs : EventArgs {
  public string Text { get; }
}

Public Event OnCharacters As OnCharactersHandler

Public Delegate Sub OnCharactersHandler(sender As Object, e As JSONCharactersEventArgs)

Public Class JSONCharactersEventArgs Inherits EventArgs
  Public ReadOnly Property Text As String
End Class

Remarks

The Characters event provides the plaintext content of the JSON document (i.e., the text inside the elements). 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.

EndDocument Event (JSON Component)

This event fires when the end of a JSON document is encountered.

Syntax

public event OnEndDocumentHandler OnEndDocument;

public delegate void OnEndDocumentHandler(object sender, JSONEndDocumentEventArgs e);

public class JSONEndDocumentEventArgs : EventArgs {
}

Public Event OnEndDocument As OnEndDocumentHandler

Public Delegate Sub OnEndDocumentHandler(sender As Object, e As JSONEndDocumentEventArgs)

Public Class JSONEndDocumentEventArgs Inherits EventArgs
End Class

Remarks

This event fires when parsing of a JSON document ends. This event may fire multiple times if InputFormat is set to a value that accepts multiple JSON documents.

EndElement Event (JSON Component)

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

Syntax

public event OnEndElementHandler OnEndElement;

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

public class JSONEndElementEventArgs : EventArgs {
  public string Element { get; }
}

Public Event OnEndElement As OnEndElementHandler

Public Delegate Sub OnEndElementHandler(sender As Object, e As JSONEndElementEventArgs)

Public Class JSONEndElementEventArgs Inherits EventArgs
  Public ReadOnly Property Element As String
End Class

Remarks

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

The element name is provided by the Element parameter.

Error Event (JSON Component)

Fired when information is available about errors during data delivery.

Syntax

public event OnErrorHandler OnError;

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

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

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As JSONErrorEventArgs)

Public Class JSONErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

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 section.

IgnorableWhitespace Event (JSON Component)

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

Syntax

public event OnIgnorableWhitespaceHandler OnIgnorableWhitespace;

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

public class JSONIgnorableWhitespaceEventArgs : EventArgs {
  public string Text { get; }
}

Public Event OnIgnorableWhitespace As OnIgnorableWhitespaceHandler

Public Delegate Sub OnIgnorableWhitespaceHandler(sender As Object, e As JSONIgnorableWhitespaceEventArgs)

Public Class JSONIgnorableWhitespaceEventArgs Inherits EventArgs
  Public ReadOnly Property Text As String
End Class

Remarks

The ignorable whitespace section is provided by the Text parameter.

JSON Event (JSON Component)

This event fires with the JSON data being written.

Syntax

public event OnJSONHandler OnJSON;

public delegate void OnJSONHandler(object sender, JSONJSONEventArgs e);

public class JSONJSONEventArgs : EventArgs {
  public string Text { get; }
}

Public Event OnJSON As OnJSONHandler

Public Delegate Sub OnJSONHandler(sender As Object, e As JSONJSONEventArgs)

Public Class JSONJSONEventArgs Inherits EventArgs
  Public ReadOnly Property Text As String
End Class

Remarks

This event fires when output data are written.

Text contains the JSON data currently being written.

StartDocument Event (JSON Component)

This event fires when the start of a new JSON document is encountered.

Syntax

public event OnStartDocumentHandler OnStartDocument;

public delegate void OnStartDocumentHandler(object sender, JSONStartDocumentEventArgs e);

public class JSONStartDocumentEventArgs : EventArgs {
}

Public Event OnStartDocument As OnStartDocumentHandler

Public Delegate Sub OnStartDocumentHandler(sender As Object, e As JSONStartDocumentEventArgs)

Public Class JSONStartDocumentEventArgs Inherits EventArgs
End Class

Remarks

This event fires when parsing of a JSON document begins. This event may fire multiple times if InputFormat is set to a value that accepts multiple JSON documents.

StartElement Event (JSON Component)

This event is fired when a new element is encountered in the document.

Syntax

public event OnStartElementHandler OnStartElement;

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

public class JSONStartElementEventArgs : EventArgs {
  public string Element { get; }
}

Public Event OnStartElement As OnStartElementHandler

Public Delegate Sub OnStartElementHandler(sender As Object, e As JSONStartElementEventArgs)

Public Class JSONStartElementEventArgs Inherits EventArgs
  Public ReadOnly Property Element As String
End Class

Remarks

The StartElement event is fired when a new element is found in the document.

The element name is provided through the Element parameter.

JSONElement Type

This type describes an element contained within the JSON document.

Remarks

This type describes a JSON element.

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

The following fields are available:
  • ElementType
  • Name
  • XText

    • Fields

    ElementType
    TXElementTypes (read-only)
    Default: 0

    The ElementType field indicates the data type of the element.

    Possible values are as follows:

    • 0 (Object)
    • 1 (Array)
    • 2 (String)
    • 3 (Number)
    • 4 (Bool)
    • 5 (Null)
    • 6 (Raw)

    Name
    string (read-only)
    Default: ""

    The Name field provides the name of the element. For elements within an array, the Name field will be empty.

    XText
    string (read-only)
    Default: ""

    This field contains the text of the element.

    Constructors

    public JSONElement();

    Public JSONElement()

    Config Settings (JSON 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.

    JSON Config Settings

    CacheContent:   If true, the original JSON is stored internally in a buffer.

    This configuration setting controls whether or not the component retains the entire original JSON data in a buffer. This is used to retain the original JSON as opposed to returning generated JSON after parsing. The default value is True.

    Charset:   Specifies the charset used when encoding data.

    Set this value to specify the charset that is used when encoding data. 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 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 is closed after processing is complete. The default value is True.

    ElementXPath:   The XPath value for the current element in the document.

    This configuration setting holds the current XPath value when the document is parsed. When queried from inside the StartElement event, the corresponding element's XPath value will be returned. For instance:

    string elementXPath = json.Config("ElementXPath");

    Note: The BuildDOM property must be set to False.

    EscapeForwardSlashes:   Whether to escape forward slashes when writing a JSON object.

    This configuration setting specifies whether forward slashes (/) are escaped when creating a JSON object using the component. This does not affect parsing of JSON. It is applicable only when JSON values are written.

    InputFormat:   Specifies the input format used in JSON streaming.

    This configuration setting specifies how JSON documents are formatted as they are input to the component. This setting is designed for use when data are provided via JSON streaming. This means multiple documents may be parsed by the component. This setting is applicable only when BuildDOM is set to False. Possible values are as follows:

    Value Description
    0 (None - default) Only a single JSON document is expected. Use this when a single JSON document is being parsed (most cases).
    1 (Line Delimited) Multiple documents are separated by carriage return (CR), line feed (LF), or CRLF character sequences.
    2 (Record Separated) A defined start and end delimiter separate documents. See RecordStartDelimiter and RecordEndDelimiter.
    3 (Concatenated) New documents begin immediately after the previous documents end; no characters or delimiters separate the documents.

    PrettyPrint:   Determines whether output is on one line or "pretty printed".

    The value of this configuration setting determines whether output is generated as a single line of JSON or as multiple "pretty printed" lines. The following example code, provides a better understanding of this configuration setting: json.Config("PrettyPrint=true"); // false json.StartObject(); json.PutName("data"); json.StartObject(); json.PutProperty("id", "3", 3); json.PutProperty("first_name", "Emma", 2); json.PutProperty("last_name", "Wong", 2); json.PutProperty("avatar", "https://s3.amazonaws.com/uifaces/faces/twitter/olegpogodaev/128.jpg", 2); json.EndObject(); json.EndObject(); json.Flush(); Console.WriteLine(json.OutputData); With PrettyPrint set to False (the default), the output would look like this: 

    {"data":{"id":3,"first_name":"Emma","last_name":"Wong","avatar":"https:\/\/s3.amazonaws.com\/uifaces\/faces\/twitter\/olegpogodaev\/128.jpg"}}
    With PrettyPrint set to True, the output instead would look like this: 
    {
  "data": {
    "id": 3,
    "first_name": "Emma",
    "last_name": "Wong",
    "avatar": "https:\/\/s3.amazonaws.com\/uifaces\/faces\/twitter\/olegpogodaev\/128.jpg"
  }
}
    The default value is False.
    RecordEndDelimiter:   The character sequence after the end of a JSON document.

    This configuration setting is used in conjunction with InputFormat to specify the character sequence that is expected after the end of a JSON document.

    RecordStartDelimiter:   The character sequence before the start of a JSON document.

    This configuration setting is used in conjunction with InputFormat to specify the character sequence that is expected before the start of a JSON document.

    StringProcessingOptions:   Defines options to use when processing string values.

    This configuration setting determines what additional processing is performed on string values during parsing. By default, no additional processing is performed and the string is returned as is from the document. Strings also may be unquoted, unescaped, or both. Possible values follow:

    0 (none - default)No additional processing is performed.
    1 (unquote) Strings are unquoted.
    2 (unescape) Any escaped sequences are unescaped.
    3 (unquote and unescape) Values are both unquoted and unescaped.
    For instance, given the JSON element: 
    "example" : "value\ntest"
    The following table shows the resulting value for the XText of the element:
    StringProcessingOptionOutput
    0 (none) 
    "value\ntest"
    1 (unquote) 
    value\ntest
    2 (unescape) 
    "value
test"
    3 (unquote and unescape) 
    value
test
    XPathNotation:   Specifies the expected format when setting XPath.

    This configuration setting optionally specifies the expected input format when setting XPath. Possible values follow:

    • 0 (Auto - default)
    • 1 (XPath)
    • 2 (JSONPath)
    In most cases, the default of 0 (Auto) is sufficient. The component will determine whether the path value is in XPath or JSONPath format automatically. If desired, the type may be explicitly set to either XPath or JSONPath using the values above.

    Trappable Errors (JSON Component)

    JSON Errors

    10231   Unbalanced element tag.
    10232   Invalid JSON markup.
    10233   Invalid XPath.
    10234   DOM tree unavailable (set BuildDOM to True and reparse).

    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.
    208   No such child.
    209   Top element does not match start of path.
    210   DOM tree unavailable (set BuildDOM to True and reparse).
    302   Cannot open file.
    401   Invalid XML would be generated.
    402   An invalid XML name has been specified.