GotoExpression GotoExpression GotoExpression GotoExpression Class

定義

無条件ジャンプを表します。Represents an unconditional jump. return ステートメント、break と continue ステートメントなど、各種のジャンプがこれに該当します。This includes return statements, break and continue statements, and other jumps.

public ref class GotoExpression sealed : System::Linq::Expressions::Expression
public sealed class GotoExpression : System.Linq.Expressions.Expression
type GotoExpression = class
    inherit Expression
Public NotInheritable Class GotoExpression
Inherits Expression
継承
GotoExpressionGotoExpressionGotoExpressionGotoExpression

次の例は、 GotoExpression Gotoメソッドを使用して、オブジェクトを含む式を作成する方法を示しています。The following example demonstrates how to create an expression that contains a GotoExpression object by using the Goto method.

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

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

// This block contains a GotoExpression.
// 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("GoTo")),
        Expression.Goto(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:
//
// GoTo

// "Other Work" is not printed because 
// the GoTo expression transfers execution from Expression.GoTo(returnTarget)
// to Expression.Label(returnTarget).
' Add the following directive to your file:
' Imports System.Linq.Expressions  

' A label expression of the void type that is the target for the GoToExpression.
Dim returnTarget As LabelTarget = Expression.Label()

' This block contains a GotoExpression.
' 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("GoTo")),
          Expression.Goto(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:
'
' GoTo

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

プロパティ

CanReduce CanReduce CanReduce CanReduce

ノードをより単純なノードに変形できることを示します。Indicates that the node can be reduced to a simpler node. これが true を返す場合、Reduce() を呼び出して単純化された形式を生成できます。If this returns true, Reduce() can be called to produce the reduced form.

(Inherited from Expression)
Kind Kind Kind Kind

"go to" 式の種類。The kind of the "go to" expression. 情報提供のみを目的とします。Serves information purposes only.

NodeType NodeType NodeType NodeType

この Expression のノード型を返します。Returns the node type of this Expression.

Target Target Target Target

このノードの移動先のラベル。The target label where this node jumps to.

Type Type Type Type

この Expression が表す式の静的な型を取得します。Gets the static type of the expression that this Expression represents.

Value Value Value Value

移動先に渡される値。ターゲットの型が System.Void である場合は null。The value passed to the target, or null if the target is of type System.Void.

メソッド

Accept(ExpressionVisitor) Accept(ExpressionVisitor) Accept(ExpressionVisitor) Accept(ExpressionVisitor)

このノード型の特定の Visit メソッドにデスパッチします。Dispatches to the specific visit method for this node type. たとえば、MethodCallExpressionVisitMethodCall(MethodCallExpression) を呼び出します。For example, MethodCallExpression calls the VisitMethodCall(MethodCallExpression).

(Inherited from Expression)
Equals(Object) Equals(Object) Equals(Object) Equals(Object)

指定したオブジェクトが、現在のオブジェクトと等しいかどうかを判断します。Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

既定のハッシュ関数として機能します。Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

現在のインスタンスの Type を取得します。Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

現在の Object の簡易コピーを作成します。Creates a shallow copy of the current Object.

(Inherited from Object)
Reduce() Reduce() Reduce() Reduce()

このノードをより単純な式に変形します。Reduces this node to a simpler expression. CanReduce が true を返す場合、これは有効な式を返します。If CanReduce returns true, this should return a valid expression. このメソッドは、それ自体も単純化する必要がある別のノードを返す場合があります。This method can return another node which itself must be reduced.

(Inherited from Expression)
ReduceAndCheck() ReduceAndCheck() ReduceAndCheck() ReduceAndCheck()

このノードをより単純な式に変形します。Reduces this node to a simpler expression. CanReduce が true を返す場合、これは有効な式を返します。If CanReduce returns true, this should return a valid expression. このメソッドは、それ自体も単純化する必要がある別のノードを返す場合があります。This method can return another node which itself must be reduced.

(Inherited from Expression)
ReduceExtensions() ReduceExtensions() ReduceExtensions() ReduceExtensions()

式を既知のノード型 (拡張ノードではない型) に単純化し、それが既に既知の型である場合は単に式を返します。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)
ToString() ToString() ToString() ToString()

Expression のテキスト表現を返します。Returns a textual representation of the Expression.

(Inherited from Expression)
Update(LabelTarget, Expression) Update(LabelTarget, Expression) Update(LabelTarget, Expression) Update(LabelTarget, Expression)

この式に似た新しい式を作成しますが、指定された子を使用します。Creates a new expression that is like this one, but using the supplied children. すべての子が同じであれば、この式が返されます。If all of the children are the same, it will return this expression.

VisitChildren(ExpressionVisitor) VisitChildren(ExpressionVisitor) VisitChildren(ExpressionVisitor) VisitChildren(ExpressionVisitor)

ノードを単純化し、単純化された式の visitor デリゲートを呼び出します。Reduces the node and then calls the visitor delegate on the reduced expression. ノードを単純化できない場合、このメソッドは例外をスローします。The method throws an exception if the node is not reducible.

(Inherited from Expression)

適用対象