Expression.Assign(Expression, Expression) Méthode

Définition

Crée un BinaryExpression qui représente une opération d'assignation.Creates a BinaryExpression that represents an assignment operation.

public:
 static System::Linq::Expressions::BinaryExpression ^ Assign(System::Linq::Expressions::Expression ^ left, System::Linq::Expressions::Expression ^ right);
public static System.Linq.Expressions.BinaryExpression Assign (System.Linq.Expressions.Expression left, System.Linq.Expressions.Expression right);
static member Assign : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression -> System.Linq.Expressions.BinaryExpression
Public Shared Function Assign (left As Expression, right As Expression) As BinaryExpression

Paramètres

left
Expression

Expression auquel la propriété Left doit être égale.An Expression to set the Left property equal to.

right
Expression

Expression auquel la propriété Right doit être égale.An Expression to set the Right property equal to.

Retours

BinaryExpression dont la propriété NodeType est égale à Assign et dont les propriétés Left et Right ont les valeurs spécifiées.A BinaryExpression that has the NodeType property equal to Assign and the Left and Right properties set to the specified values.

Exemples

L’exemple de code suivant montre comment créer une expression qui représente une opération d’assignation.The following code example shows how to create an expression that represents an assignment operation.

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

// To demonstrate the assignment operation, we create a variable.
ParameterExpression variableExpr = Expression.Variable(typeof(String), "sampleVar");

// This expression represents the assignment of a value
// to a variable expression.
// It copies a value for value types, and
// copies a reference for reference types.
Expression assignExpr = Expression.Assign(
    variableExpr,
    Expression.Constant("Hello World!")
    );

// The block expression allows for executing several expressions sequentually.
// In this block, we pass the variable expression as a parameter,
// and then assign this parameter a value in the assign expression.
Expression blockExpr = Expression.Block(
    new ParameterExpression[] { variableExpr },
    assignExpr
    );

// Print out the assign expression.
Console.WriteLine(assignExpr.ToString());

// The following statement first creates an expression tree,
// then compiles it, and then executes it.  
Console.WriteLine(Expression.Lambda<Func<String>>(blockExpr).Compile()());

// This code example produces the following output:
//
// (sampleVar = "Hello World!")
// Hello World!

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

' To demonstrate the assignment operation, create a variable.
Dim variableExpr As ParameterExpression = Expression.Variable(GetType(String), "sampleVar")

' This expression represents the assignment of a value
' to a variable expression.
' It copies a value for value types, and it
' copies a reference for reference types.
Dim assignExpr As Expression = Expression.Assign(
    variableExpr,
    Expression.Constant("Hello World!")
    )

' The block expression allows for executing several expressions sequentually.
' In this block, you pass the variable expression as a parameter,
' and then assign this parameter a value in the assign expression.
Dim blockExpr As Expression = Expression.Block(
      New ParameterExpression() {variableExpr}, assignExpr
      )

' Print the assign expression.
Console.WriteLine(assignExpr.ToString())

' The following statement first creates an expression tree,
' then compiles it, and then executes it. 
Console.WriteLine(Expression.Lambda(Of Func(Of String))(blockExpr).Compile()())

' This code example produces the following output:
'
' (sampleVar = "Hello World!")
' Hello World!

Remarques

L' Assign expression copie une valeur pour les types valeur et copie une référence pour les types référence.The Assign expression copies a value for value types, and it copies a reference for reference types.

S’applique à