LambdaExpression Class
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Describes a lambda expression. This captures a block of code that is similar to a .NET method body.
public ref class LambdaExpression abstract : System::Linq::Expressions::Expression
public ref class LambdaExpression : System::Linq::Expressions::Expression
public abstract class LambdaExpression : System.Linq.Expressions.Expression
public class LambdaExpression : System.Linq.Expressions.Expression
type LambdaExpression = class
inherit Expression
Public MustInherit Class LambdaExpression
Inherits Expression
Public Class LambdaExpression
Inherits Expression
- Inheritance
- Derived
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
' 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.
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
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.
Body |
Gets the body of the lambda expression. |
Can |
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) |
Name |
Gets the name of the lambda expression. |
Node |
Returns the node type of this Expression. |
Node |
Gets the node type of this Expression. (Inherited from Expression) |
Parameters |
Gets the parameters of the lambda expression. |
Return |
Gets the return type of the lambda expression. |
Tail |
Gets the value that indicates if the lambda expression will be compiled with the tail call optimization. |
Type |
Gets the static type of the expression that this Expression represents. |
Type |
Gets the static type of the expression that this Expression represents. (Inherited from Expression) |
Accept(Expression |
Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall(MethodCallExpression). (Inherited from Expression) |
Compile() |
Produces a delegate that represents the lambda expression. |
Compile(Boolean) |
Produces an interpreted or compiled delegate that represents the lambda expression. |
Compile(Debug |
Produces a delegate that represents the lambda expression. |
Compile |
Compiles the lambda into a method definition and custom debug information. |
Compile |
Compiles the lambda into a method definition. |
Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
Get |
Serves as the default hash function. (Inherited from Object) |
Get |
Gets the Type of the current instance. (Inherited from Object) |
Memberwise |
Creates a shallow copy of the current Object. (Inherited from Object) |
Reduce() |
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) |
Reduce |
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) |
Reduce |
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) |
To |
Returns a textual representation of the Expression. (Inherited from Expression) |
Visit |
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) |
מוצר | גירסאות |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.6, 2.0, 2.1 |
UWP | 10.0 |
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