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XElement.Parse Method (String, LoadOptions)

Load an XElement from a string that contains XML, optionally preserving white space and retaining line information.

Namespace:  System.Xml.Linq
Assemblies:   System.Xml.Linq (in System.Xml.Linq.dll)
  System.Xml.XDocument (in System.Xml.XDocument.dll)

'Declaration
Public Shared Function Parse ( _
	text As String, _
	options As LoadOptions _
) As XElement

Parameters

text
Type: System.String

A String that contains XML.

options
Type: System.Xml.Linq.LoadOptions

A LoadOptions that specifies white space behavior, and whether to load base URI and line information.

Return Value

Type: System.Xml.Linq.XElement
An XElement populated from the string that contains XML.

If the source XML is indented, setting the PreserveWhitespace flag in options causes the reader to read all white space in the source XML. Nodes of type XText are created for both significant and insignificant white space.

If the source XML is indented, not setting the PreserveWhitespace flag in options causes the reader to ignore all of the insignificant white space in the source XML. The XML tree is created without any text nodes for insignificant white space.

If the source XML is not indented, setting the PreserveWhitespace flag in options has no effect. Significant white space is still preserved, and there are no spans of insignificant white space that could cause the creation of more white space text nodes.

For more information, see Preserving White Space while Loading or Parsing XML and Preserving White Space While Serializing.

Setting SetBaseUri will have no effect when parsing from a String.

The XmlReader may have a valid line information or not. If you set SetLineInfo, the line information will be set in the XML tree from the line information that is reported by the XmlReader.

There is a performance penalty if you set the SetLineInfo flag.

The line information is accurate immediately after loading the XML document. If you modify the XML tree after loading the document, the line information may become meaningless.

LINQ to XML's loading functionality is built upon XmlReader. Therefore, you might catch any exceptions that are thrown by the XmlReader.Create overload methods and the XmlReader methods that read and parse the document.

The following example parses a string into an XElement in two different ways: preserving white space, and not preserving white space. It then uses a query to determine the number of white space nodes in the resulting XML tree.

Dim whiteSpaceNodes As Integer

Dim xmlTree1 As XElement = XElement.Parse("<Root> <Child> </Child> </Root>", LoadOptions.None)
whiteSpaceNodes = xmlTree1 _
    .DescendantNodesAndSelf() _
    .OfType(Of XText)() _
    .Where(Function(ByVal tNode As XNode) tNode.ToString().Trim().Length = 0) _
    .Count()
Console.WriteLine("Count of white space nodes (not preserving whitespace): {0}", whiteSpaceNodes)

Dim xmlTree2 As XElement = XElement.Parse("<Root> <Child> </Child> </Root>", LoadOptions.PreserveWhitespace)
whiteSpaceNodes = xmlTree2 _
    .DescendantNodesAndSelf() _
    .OfType(Of XText)() _
    .Where(Function(ByVal tNode As XNode) tNode.ToString().Trim().Length = 0) _
    .Count()
Console.WriteLine("Count of white space nodes (preserving whitespace): {0}", whiteSpaceNodes)

This example produces the following output:

Count of white space nodes (not preserving whitespace): 0
Count of white space nodes (preserving whitespace): 3

The following example retains line information as it parses the string.

Dim markup As String = _
"<Root>" & Environment.NewLine & _
"    <Child>" & Environment.NewLine & _
"        <GrandChild/>" & Environment.NewLine & _
"    </Child>" & Environment.NewLine & _
"</Root>"

Dim xRoot As XElement = XElement.Parse(markup, LoadOptions.SetLineInfo)
Console.WriteLine("{0}{1}{2}", _
    "Element Name".PadRight(20), _
    "Line".PadRight(5), _
    "Position")
Console.WriteLine("{0}{1}{2}", _
    "------------".PadRight(20), _
    "----".PadRight(5), _
    "--------")
For Each e As XElement In xRoot.DescendantsAndSelf()
    Console.WriteLine("{0}{1}{2}", _
        ("".PadRight(e.Ancestors().Count() * 2) & e.Name.ToString).PadRight(20), _
        DirectCast(e, IXmlLineInfo).LineNumber.ToString().PadRight(5), _
        DirectCast(e, IXmlLineInfo).LinePosition)
Next

This example produces the following output:

Element Name        Line Position
------------        ---- --------
Root                1    2
  Child             2    6
    GrandChild      3    10

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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