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LambdaExpression Class

Describes a lambda expression. This captures a block of code that is similar to a .NET method body.

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

'Declaration
Public MustInherit Class LambdaExpression _
	Inherits Expression

The LambdaExpression type exposes the following members.

  NameDescription
Public propertySupported by Silverlight for Windows PhoneBodyGets the body of the lambda expression.
Public propertyCanReduceIndicates that the node can be reduced to a simpler node. If this returns true, Reduce() can be called to produce the reduced form. (Inherited from Expression.)
Public propertyNameGets the name of the lambda expression.
Public propertySupported by Silverlight for Windows PhoneNodeTypeReturns the node type of this Expression. (Overrides Expression.NodeType.)

In Silverlight for Windows Phone Windows Phone OS 7.1, this member is inherited from Expression.NodeType.


In XNA Framework Windows Phone OS 7.0, this member is inherited from Expression.NodeType.
Public propertySupported by Silverlight for Windows PhoneParametersGets the parameters of the lambda expression.
Public propertyReturnTypeGets the return type of the lambda expression.
Public propertyTailCallGets the value that indicates if the lambda expression will be compiled with the tail call optimization.
Public propertySupported by Silverlight for Windows PhoneTypeGets the static type of the expression that this Expression represents. (Overrides Expression.Type.)

In Silverlight for Windows Phone Windows Phone OS 7.1, this member is inherited from Expression.Type.


In XNA Framework Windows Phone OS 7.0, this member is inherited from Expression.Type.
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  NameDescription
Protected methodAcceptDispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall. (Inherited from Expression.)
Public methodSupported by Silverlight for Windows PhoneCompileProduces a delegate that represents the lambda expression.
Public methodCompile(DebugInfoGenerator)Produces a delegate that represents the lambda expression.
Public methodCompileToMethod(MethodBuilder)Compiles the lambda into a method definition.
Public methodCompileToMethod(MethodBuilder, DebugInfoGenerator)Compiles the lambda into a method definition and custom debug information.
Public methodSupported by Silverlight for Windows PhoneEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows PhoneFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Silverlight for Windows PhoneGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by Silverlight for Windows PhoneGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows PhoneMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodReduceReduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced. (Inherited from Expression.)
Public methodReduceAndCheckReduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced. (Inherited from Expression.)
Public methodReduceExtensionsReduces the expression to a known node type (that is not an Extension node) or just returns the expression if it is already a known type. (Inherited from Expression.)
Public methodSupported by Silverlight for Windows PhoneToStringReturns a textual representation of the Expression. (Inherited from Expression.)
Protected methodVisitChildrenReduces the node and then calls the visitor delegate on the reduced expression. The method throws an exception if the node is not reducible. (Inherited from Expression.)
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The LambdaExpression type represents a lambda expression in the form of an expression tree. The Expression(Of TDelegate) type, which derives from LambdaExpression and captures the type of the lambda expression more explicitly, can also be used to represent a lambda expression. At runtime, an expression tree node that represents a lambda expression is always of type Expression(Of TDelegate).

The value of the NodeType property of a LambdaExpression is Lambda.

Use the Lambda factory methods to create a LambdaExpression object.

The following example demonstrates how to create an expression that represents a lambda expression that adds 1 to the passed argument by using the Lambda method.


' Add the following directive to your file:
' Imports System.Linq.Expressions  

' A parameter for the lambda expression.
Dim paramExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "arg")

' This expression represents a lambda expression
' that adds 1 to the parameter value.
Dim lambdaExpr As LambdaExpression = Expression.Lambda(
        Expression.Add(
            paramExpr,
            Expression.Constant(1)
        ),
        New List(Of ParameterExpression)() From {paramExpr}
    )

' Print out the expression.
outputBlock.Text &= lambdaExpr.ToString() & vbCrLf

' Compile and run the lamda expression.
' The value of the parameter is 1.
outputBlock.Text &= lambdaExpr.Compile().DynamicInvoke(1).ToString() & vbCrLf

' This code example produces the following output:
'
' arg => (arg +1)
' 2


Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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