Expression.Continue 方法

定义

命名空间:

System.Linq.Expressions

程序集:

System.Linq.Expressions.dll

创建表示 continue 语句的 GotoExpression。

重载

Continue(LabelTarget)	创建表示 continue 语句的 GotoExpression。
Continue(LabelTarget, Type)	创建表示具有指定类型的 continue 语句的 GotoExpression。

Continue(LabelTarget)

Source:

GotoExpression.cs

创建表示 continue 语句的 GotoExpression。

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

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

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

Public Shared Function Continue (target As LabelTarget) As GotoExpression

参数

target

LabelTarget

GotoExpression 将跳转到的 LabelTarget。

返回

GotoExpression

Kind 等于 Continue 的 GotoExpression，Target 属性设置为 target，在跳转时要传递给目标标签的 null 值。

示例

以下示例演示如何创建使用 Continue 方法的循环表达式。

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

// A label that is used by a break statement and a loop.
LabelTarget breakLabel = Expression.Label();

// A label that is used by the Continue statement and the loop it refers to.
LabelTarget continueLabel = Expression.Label();

// This expression represents a Continue statement.
Expression continueExpr = Expression.Continue(continueLabel);

// A variable that triggers the exit from the loop.
ParameterExpression count = Expression.Parameter(typeof(int));

// A loop statement.
Expression loopExpr = Expression.Loop(
    Expression.Block(
        Expression.IfThen(
            Expression.GreaterThan(count, Expression.Constant(3)),
            Expression.Break(breakLabel)
        ),
        Expression.PreIncrementAssign(count),
        Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("Loop")
                ),
        continueExpr,
        Expression.PreDecrementAssign(count)
    ),
    breakLabel,
    continueLabel
);

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
// Without the Continue statement, the loop would go on forever.
Expression.Lambda<Action<int>>(loopExpr, count).Compile()(1);

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

' Add the following directive to your file:
' Imports System.Linq.Expressions  

' A label that is used by a break statement and a loop. 
Dim breakLabel As LabelTarget = Expression.Label()

' A label that is used by the Continue statement and the loop it refers to.
Dim continueLabel As LabelTarget = Expression.Label()

' This expression represents a Continue statement.
Dim continueExpr As Expression = Expression.Continue(continueLabel)

' A variable that triggers the exit from the loop.
Dim count As ParameterExpression = Expression.Parameter(GetType(Integer))

' A loop statement.
Dim loopExpr As Expression = Expression.Loop(
       Expression.Block(
           Expression.IfThen(
               Expression.GreaterThan(count, Expression.Constant(3)),
               Expression.Break(breakLabel)
           ),
           Expression.PreIncrementAssign(count),
           Expression.Call(
                       Nothing,
                       GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
                       Expression.Constant("Loop")
                   ),
           continueExpr,
           Expression.PreDecrementAssign(count)
       ),
       breakLabel,
       continueLabel
   )

' The following statement first creates an expression tree,
' then compiles it, and then runs it.
' Without the Continue statement, the loop would go on forever.
Expression.Lambda(Of Action(Of Integer))(loopExpr, count).Compile()(1)

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

Continue(LabelTarget, Type)

Source:

GotoExpression.cs

创建表示具有指定类型的 continue 语句的 GotoExpression。

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

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

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

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

参数

target

LabelTarget

GotoExpression 将跳转到的 LabelTarget。

type

Type

要设置等于 Type 属性的 Type。

返回

GotoExpression

Kind 等于 Continue 的 GotoExpression，Target 属性设置为 target，Type 属性设置为 type，在跳转时要传递给目标标签的 null 值。