Expression.Assign Method (Expression, Expression)

 

Creates a BinaryExpression that represents an assignment operation.

Namespace:   System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

public static BinaryExpression Assign(
	Expression left,
	Expression right
)

Parameters

left
Type: System.Linq.Expressions.Expression

An Expression to set the Left property equal to.

right
Type: System.Linq.Expressions.Expression

An Expression to set the Right property equal to.

Return Value

Type: System.Linq.Expressions.BinaryExpression

A BinaryExpression that has the NodeType property equal to Assign and the Left and Right properties set to the specified values.

The Assign expression copies a value for value types, and it copies a reference for reference types.

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!

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
Return to top
Show: