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LambdaExpression Class

LambdaExpression Class

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

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

public abstract class LambdaExpression : Expression

The LambdaExpression type exposes the following members.

  NameDescription
Public propertySupported by Portable Class LibraryBodyGets the body of the lambda expression.
Public propertySupported by Portable Class LibraryCanReduceIndicates 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 propertySupported by Portable Class LibraryNameGets the name of the lambda expression.
Public propertySupported by Portable Class LibraryNodeTypeReturns the node type of this Expression. (Overrides Expression.NodeType.)
Public propertySupported by Portable Class LibraryParametersGets the parameters of the lambda expression.
Public propertySupported by Portable Class LibraryReturnTypeGets the return type of the lambda expression.
Public propertySupported by Portable Class LibraryTailCallGets the value that indicates if the lambda expression will be compiled with the tail call optimization.
Public propertySupported by Portable Class LibraryTypeGets the static type of the expression that this Expression represents. (Overrides Expression.Type.)
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  NameDescription
Protected methodSupported by Portable Class LibraryAcceptDispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall. (Inherited from Expression.)
Public methodSupported by Portable Class LibraryCompile()Produces 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 Portable Class LibraryEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodSupported by Portable Class LibraryFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Portable Class LibraryGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodSupported by Portable Class LibraryGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Portable Class LibraryMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by Portable Class LibraryReduceReduces 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 methodSupported by Portable Class LibraryReduceAndCheckReduces 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 methodSupported by Portable Class LibraryReduceExtensionsReduces 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 Portable Class LibraryToStringReturns a textual representation of the Expression. (Inherited from Expression.)
Protected methodSupported by Portable Class LibraryVisitChildrenReduces 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<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<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: 
// using System.Linq.Expressions;   

// A parameter for the lambda expression.
ParameterExpression paramExpr = Expression.Parameter(typeof(int), "arg");

// This expression represents a lambda expression 
// that adds 1 to the parameter value.
LambdaExpression lambdaExpr = Expression.Lambda(
    Expression.Add(
        paramExpr,
        Expression.Constant(1)
    ),
    new List<ParameterExpression>() { paramExpr }
);

// Print out the expression.
Console.WriteLine(lambdaExpr);

// Compile and run the lamda expression. 
// The value of the parameter is 1.
Console.WriteLine(lambdaExpr.Compile().DynamicInvoke(1));

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.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

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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