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Expression.Label Method

Creates a LabelTarget representing a label with void type and no name.

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

public static LabelTarget Label()

The following example demonstrates how to create an expression that contains a LabelTarget object.

// Add the following directive to the file: 
// using System.Linq.Expressions;   

// A label expression of the void type that is the target for Expression.Return().
LabelTarget returnTarget = Expression.Label();

// This block contains a GotoExpression that represents a return statement with no value. 
// It transfers execution to a label expression that is initialized with the same LabelTarget as the GotoExpression. 
// The types of the GotoExpression, label expression, and LabelTarget must match.
BlockExpression blockExpr =
    Expression.Block(
        Expression.Call(typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) }), Expression.Constant("Return")),
        Expression.Return(returnTarget),
        Expression.Call(typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) }), Expression.Constant("Other Work")),
        Expression.Label(returnTarget)
    );

// The following statement first creates an expression tree, 
// then compiles it, and then runs it.
Expression.Lambda<Action>(blockExpr).Compile()();

// This code example produces the following output: 
// 
// Return 

// "Other Work" is not printed because 
// the Return expression transfers execution from Expression.Return(returnTarget) 
// to Expression.Label(returnTarget).

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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