Expression.Loop Méthode

Définition

Crée un LoopExpression.Creates a LoopExpression.

Surcharges

Loop(Expression)

Crée un LoopExpression avec le corps donné.Creates a LoopExpression with the given body.

Loop(Expression, LabelTarget)

Crée un objet LoopExpression avec le corps et la cible d'instruction Break donnés.Creates a LoopExpression with the given body and break target.

Loop(Expression, LabelTarget, LabelTarget)

Crée un LoopExpression avec le corps donné.Creates a LoopExpression with the given body.

Loop(Expression)

Crée un LoopExpression avec le corps donné.Creates a LoopExpression with the given body.

public:
 static System::Linq::Expressions::LoopExpression ^ Loop(System::Linq::Expressions::Expression ^ body);
public static System.Linq.Expressions.LoopExpression Loop (System.Linq.Expressions.Expression body);
static member Loop : System.Linq.Expressions.Expression -> System.Linq.Expressions.LoopExpression
Public Shared Function Loop (body As Expression) As LoopExpression

Paramètres

body
Expression

Corps de la boucle.The body of the loop.

Retours

Élément LoopExpression créé.The created LoopExpression.

Loop(Expression, LabelTarget)

Crée un objet LoopExpression avec le corps et la cible d'instruction Break donnés.Creates a LoopExpression with the given body and break target.

public:
 static System::Linq::Expressions::LoopExpression ^ Loop(System::Linq::Expressions::Expression ^ body, System::Linq::Expressions::LabelTarget ^ break);
public static System.Linq.Expressions.LoopExpression Loop (System.Linq.Expressions.Expression body, System.Linq.Expressions.LabelTarget break);
static member Loop : System.Linq.Expressions.Expression * System.Linq.Expressions.LabelTarget -> System.Linq.Expressions.LoopExpression
Public Shared Function Loop (body As Expression, break As LabelTarget) As LoopExpression

Paramètres

body
Expression

Corps de la boucle.The body of the loop.

break
LabelTarget

Cible d'instruction Break utilisée par le corps de la boucle.The break target used by the loop body.

Retours

Élément LoopExpression créé.The created LoopExpression.

Exemples

L’exemple suivant montre comment créer une expression de bloc qui contient un LoopExpression objet.The following example demonstrates how to create a block expression that contains a LoopExpression object.

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

// Creating a parameter expression.
ParameterExpression value = Expression.Parameter(typeof(int), "value");

// Creating an expression to hold a local variable. 
ParameterExpression result = Expression.Parameter(typeof(int), "result");

// Creating a label to jump to from a loop.
LabelTarget label = Expression.Label(typeof(int));

// Creating a method body.
BlockExpression block = Expression.Block(
    new[] { result },
    Expression.Assign(result, Expression.Constant(1)),
        Expression.Loop(
           Expression.IfThenElse(
               Expression.GreaterThan(value, Expression.Constant(1)),
               Expression.MultiplyAssign(result,
                   Expression.PostDecrementAssign(value)),
               Expression.Break(label, result)
           ),
       label
    )
);

// Compile and run an expression tree.
int factorial = Expression.Lambda<Func<int, int>>(block, value).Compile()(5);

Console.WriteLine(factorial);

// This code example produces the following output:
//
// 120
' Add the following directive to the file:
' Imports System.Linq.Expressions  

' Creating a parameter expression.
Dim value As ParameterExpression =
    Expression.Parameter(GetType(Integer), "value")

' Creating an expression to hold a local variable. 
Dim result As ParameterExpression =
    Expression.Parameter(GetType(Integer), "result")

' Creating a label to jump to from a loop.
Dim label As LabelTarget = Expression.Label(GetType(Integer))

' Creating a method body.
Dim block As BlockExpression = Expression.Block(
    New ParameterExpression() {result},
    Expression.Assign(result, Expression.Constant(1)),
    Expression.Loop(
        Expression.IfThenElse(
            Expression.GreaterThan(value, Expression.Constant(1)),
            Expression.MultiplyAssign(result,
                Expression.PostDecrementAssign(value)),
            Expression.Break(label, result)
        ),
        label
    )
)

' Compile an expression tree and return a delegate.
Dim factorial As Integer =
    Expression.Lambda(Of Func(Of Integer, Integer))(block, value).Compile()(5)

Console.WriteLine(factorial)

' This code example produces the following output:
'
' 120

Loop(Expression, LabelTarget, LabelTarget)

Crée un LoopExpression avec le corps donné.Creates a LoopExpression with the given body.

public:
 static System::Linq::Expressions::LoopExpression ^ Loop(System::Linq::Expressions::Expression ^ body, System::Linq::Expressions::LabelTarget ^ break, System::Linq::Expressions::LabelTarget ^ continue);
public static System.Linq.Expressions.LoopExpression Loop (System.Linq.Expressions.Expression body, System.Linq.Expressions.LabelTarget break, System.Linq.Expressions.LabelTarget continue);
static member Loop : System.Linq.Expressions.Expression * System.Linq.Expressions.LabelTarget * System.Linq.Expressions.LabelTarget -> System.Linq.Expressions.LoopExpression
Public Shared Function Loop (body As Expression, break As LabelTarget, continue As LabelTarget) As LoopExpression

Paramètres

body
Expression

Corps de la boucle.The body of the loop.

break
LabelTarget

Cible d'instruction Break utilisée par le corps de la boucle.The break target used by the loop body.

continue
LabelTarget

Cible d'instruction Continue utilisée par le corps de la boucle.The continue target used by the loop body.

Retours

Élément LoopExpression créé.The created LoopExpression.

S’applique à