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

 
equivalentCodeEntity

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

This API is not CLS-compliant.

Namespace:   System.Xml.Linq
Assembly:  System.Xml.Linq (in System.Xml.Linq.dll)

Public Shared Narrowing Operator CType (
	element As XElement
) As Nullable(Of Boolean)

Parameters

element
Type: System.Xml.Linq.XElement

The XElement 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 XElement.

Exception Condition
FormatException

The element does not contain a valid Boolean value.

When converting to Nullable(Of T) of 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 element with boolean content. It then retrieves the value by casting to Nullable(Of T) of Boolean.


                Dim root As XElement = _ 
        <Root>
            <BoolValue1>true</BoolValue1>
            <BoolValue2>false</BoolValue2>
        </Root>


Dim value1 As Nullable(Of Boolean) = CType(root.Element("BoolValue1"), Nullable(Of Boolean))
Dim value2 As Nullable(Of Boolean) = CType(root.Element("BoolValue2"), Nullable(Of Boolean))
Console.WriteLine("Nullable Boolean: value1={0}", IIf(value1.HasValue, value1.ToString(), "null"))
Console.WriteLine("Nullable Boolean: value2={0}", IIf(value2.HasValue, value2.ToString(), "null"))

This example produces the following output:

Nullable Boolean: value1=True
Nullable Boolean: value2=False

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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