Expression.Return 方法

public:
 static System::Linq::Expressions::GotoExpression ^ Return(System::Linq::Expressions::LabelTarget ^ target);

public static System.Linq.Expressions.GotoExpression Return(System.Linq.Expressions.LabelTarget target);

static member Return : System.Linq.Expressions.LabelTarget -> System.Linq.Expressions.GotoExpression

Public Shared Function Return (target As LabelTarget) As GotoExpression

参数

返回

一个等于 Return、属性设置为 /> 和一个在跳转时传递给目标标签的 null 值。

public:
 static System::Linq::Expressions::GotoExpression ^ Return(System::Linq::Expressions::LabelTarget ^ target, System::Linq::Expressions::Expression ^ value);

public static System.Linq.Expressions.GotoExpression Return(System.Linq.Expressions.LabelTarget target, System.Linq.Expressions.Expression value);

static member Return : System.Linq.Expressions.LabelTarget * System.Linq.Expressions.Expression -> System.Linq.Expressions.GotoExpression

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

参数

返回

等于 Continue 的属性设置为/>，并在跳转时传递给目标标签。

示例

以下示例演示如何创建包含该方法的 Return 表达式。

// 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).

' 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).

public:
 static System::Linq::Expressions::GotoExpression ^ Return(System::Linq::Expressions::LabelTarget ^ target, Type ^ type);

public static System.Linq.Expressions.GotoExpression Return(System.Linq.Expressions.LabelTarget target, Type type);

static member Return : System.Linq.Expressions.LabelTarget * Type -> System.Linq.Expressions.GotoExpression

Public Shared Function Return (target As LabelTarget, type As Type) As GotoExpression

参数

返回

一Kind个GotoExpression等于 Return、Target属性设置为 target、Type属性设置为 type 和一个在跳转时传递给目标标签的 null 值。

public:
 static System::Linq::Expressions::GotoExpression ^ Return(System::Linq::Expressions::LabelTarget ^ target, System::Linq::Expressions::Expression ^ value, Type ^ type);

public static System.Linq.Expressions.GotoExpression Return(System.Linq.Expressions.LabelTarget target, System.Linq.Expressions.Expression value, Type type);

static member Return : System.Linq.Expressions.LabelTarget * System.Linq.Expressions.Expression * Type -> System.Linq.Expressions.GotoExpression

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

参数

返回

等于 GotoExpressionKind Continue、 Target 属性设置为 target、 Type 属性设置为 type 并在 value 跳转时传递给目标标签。