Expression.Return Method (LabelTarget, Expression)

 
System_CAPS_noteNote

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Creates a GotoExpression representing a return statement. The value passed to the label upon jumping can be specified.

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

Public Shared Function Return (
	target As LabelTarget,
	value As Expression
) As GotoExpression

Parameters

target
Type: System.Linq.Expressions.LabelTarget

The LabelTarget that the GotoExpression will jump to.

value
Type: System.Linq.Expressions.Expression

The value that will be passed to the associated label upon jumping.

Return Value

Type: System.Linq.Expressions.GotoExpression

A GotoExpression with Kind equal to Continue, the Target property set to target, and value to be passed to the target label upon jumping.

The following example demonstrates how to create an expression that contains the Return method.

' Add the following directive to the file:
' Imports System.Linq.Expressions  
' A label expression of the void type that is the target for Expression.Return().
Dim returnTarget As LabelTarget = 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.
Dim blockExpr As BlockExpression =
      Expression.Block(
          Expression.Call(GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}), Expression.Constant("Return")),
          Expression.Return(returnTarget),
          Expression.Call(GetType(Console).GetMethod("WriteLine", New Type() {GetType(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(Of Action)(blockExpr).Compile()()

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

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

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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