Expression.Loop Метод

Определение

Пространство имен:

System.Linq.Expressions

Сборка:

System.Linq.Expressions.dll

Создает объект LoopExpression.

Перегрузки

Loop(Expression)	Создает объект LoopExpression с заданным телом.
Loop(Expression, LabelTarget)	Создает объект LoopExpression с заданным телом и целью оператора break.
Loop(Expression, LabelTarget, LabelTarget)	Создает объект LoopExpression с заданным телом.

Loop(Expression)

Исходный код:

LoopExpression.cs

Создает объект LoopExpression с заданным телом.

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

Параметры

body

Expression

Тело цикла.

Возвращаемое значение

LoopExpression

Созданный LoopExpression.

Loop(Expression, LabelTarget)

Исходный код:

LoopExpression.cs

Создает объект LoopExpression с заданным телом и целью оператора break.

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

Параметры

body

Expression

Тело цикла.

break

LabelTarget

Цель оператора break, используемая телом цикла.

Возвращаемое значение

LoopExpression

Созданный LoopExpression.

Примеры

В следующем примере показано, как создать блочное выражение, содержащее LoopExpression объект .

// 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)

Исходный код:

LoopExpression.cs

Создает объект LoopExpression с заданным телом.

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

Параметры

body

Expression

Тело цикла.

break

LabelTarget

Цель оператора break, используемая телом цикла.

continue

LabelTarget

Цель оператора continue, используемая телом цикла.

Возвращаемое значение

LoopExpression

Созданный LoopExpression.