Windows apps
Collapse the table of content
Expand the table of content
Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

LambdaExpression Class

 
System_CAPS_noteNote

The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

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)

System.Object
  System.Linq.Expressions.Expression
    System.Linq.Expressions.LambdaExpression
      System.Linq.Expressions.Expression<TDelegate>

public abstract class LambdaExpression : Expression

NameDescription
System_CAPS_pubpropertyBody

Gets the body of the lambda expression.

System_CAPS_pubpropertyCanReduce

Indicates 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.)

System_CAPS_pubpropertyName

Gets the name of the lambda expression.

System_CAPS_pubpropertyNodeType

Returns the node type of this Expression.(Overrides Expression.NodeType.)

System_CAPS_pubpropertyParameters

Gets the parameters of the lambda expression.

System_CAPS_pubpropertyReturnType

Gets the return type of the lambda expression.

System_CAPS_pubpropertyTailCall

Gets the value that indicates if the lambda expression will be compiled with the tail call optimization.

System_CAPS_pubpropertyType

Gets the static type of the expression that this Expression represents.(Overrides Expression.Type.)

NameDescription
System_CAPS_protmethodAccept(ExpressionVisitor)

Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall.(Inherited from Expression.)

System_CAPS_pubmethodCompile()

Produces a delegate that represents the lambda expression.

System_CAPS_pubmethodCompile(Boolean)

Produces an interpreted or compiled delegate that represents the lambda expression.

System_CAPS_pubmethodCompile(DebugInfoGenerator)

Produces a delegate that represents the lambda expression.

System_CAPS_pubmethodCompileToMethod(MethodBuilder)

Compiles the lambda into a method definition.

System_CAPS_pubmethodCompileToMethod(MethodBuilder, DebugInfoGenerator)

Compiles the lambda into a method definition and custom debug information.

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethodReduce()

Reduces 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.)

System_CAPS_pubmethodReduceAndCheck()

Reduces 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.)

System_CAPS_pubmethodReduceExtensions()

Reduces 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.)

System_CAPS_pubmethodToString()

Returns a textual representation of the Expression.(Inherited from Expression.)

System_CAPS_protmethodVisitChildren(ExpressionVisitor)

Reduces 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.)

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

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

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

Return to top
Show:
© 2017 Microsoft