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Explicit Conversion (XAttribute to Nullable(Boolean))

XAttribute Narrowing Conversion (XAttribute to Nullable(Of Boolean))

Cast the value of this XAttribute to a Nullable(Of T) of Boolean.

This API is not CLS-compliant. 

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

Public Shared Narrowing Operator CType ( _
	attribute As XAttribute _
) As Nullable(Of Boolean)


Type: System.Xml.Linq.XAttribute

The XAttribute to cast to Nullable(Of T) of Boolean.

Return Value

Type: System.Nullable(Of Boolean)
A Nullable(Of T) of Boolean that contains the content of this XAttribute.


The attribute does not contain a valid Boolean value.

When converting to Boolean from an attribute or element, allowed values are "0", "1", and any string that produces "true" or "false" after trimming and conversion to lower case.

The following example creates an attribute with Boolean content. It then retrieves the value by casting to Nullable(Of T) of Boolean.

Dim root As XElement = <Root BoolValue1="true" BoolValue2="false"/>
Dim bool1 As Nullable(Of Boolean) = CType(root.Attribute("BoolValue1"), Nullable(Of Boolean))
Dim bool2 As Nullable(Of Boolean) = CType(root.Attribute("BoolValue2"), Nullable(Of Boolean))
Console.WriteLine("Nullable boolean: BoolValue1={0}", bool1)
Console.WriteLine("Nullable boolean: BoolValue2={0}", bool2)

This example produces the following output:

Nullable boolean: BoolValue1=True
Nullable boolean: BoolValue2=False

.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

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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