Expression.TypeAs Method (Expression, Type)

 

Creates a UnaryExpression that represents an explicit reference or boxing conversion where null is supplied if the conversion fails.

Namespace:   System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

public static UnaryExpression TypeAs(
	Expression expression,
	Type type
)

Parameters

expression
Type: System.Linq.Expressions.Expression

An Expression to set the Operand property equal to.

type
Type: System.Type

A Type to set the Type property equal to.

Return Value

Type: System.Linq.Expressions.UnaryExpression

A UnaryExpression that has the NodeType property equal to TypeAs and the Operand and Type properties set to the specified values.

Exception Condition
ArgumentNullException

expression or type is null.

The Method property of the resulting UnaryExpression is null. The IsLifted and IsLiftedToNull properties are both false.

The following example demonstrates how to use the TypeAs(Expression, Type) method to create a UnaryExpression that represents the reference conversion of a non-nullable integer expression to the nullable integer type.

// Create a UnaryExpression that represents a
// conversion of an int to an int?.
System.Linq.Expressions.UnaryExpression typeAsExpression =
    System.Linq.Expressions.Expression.TypeAs(
        System.Linq.Expressions.Expression.Constant(34, typeof(int)),
        typeof(int?));

Console.WriteLine(typeAsExpression.ToString());

// This code produces the following output:
//
// (34 As Nullable`1)

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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