Expression.Block Method (IEnumerable<ParameterExpression>, IEnumerable<Expression>)


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Creates a BlockExpression that contains the given variables and expressions.

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

public static BlockExpression Block(
	IEnumerable<ParameterExpression> variables,
	IEnumerable<Expression> expressions


Type: System.Collections.Generic.IEnumerable<ParameterExpression>

The variables in the block.

Type: System.Collections.Generic.IEnumerable<Expression>

The expressions in the block.

When the block expression is executed, it returns the value of the last expression in the block.

The following code example shows how to pass a parameter to a block expression and process this parameter within a block.

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

// This block has a parameter expression
// that represents a variable within the block scope.
// It assigns a value to the variable,
// and then adds a constant to the assigned value. 

ParameterExpression varExpr = Expression.Variable(typeof(int), "sampleVar");
BlockExpression blockExpr = Expression.Block(
    new ParameterExpression[] { varExpr },
    Expression.Assign(varExpr, Expression.Constant(1)),
    Expression.Add(varExpr, Expression.Constant(5))

// Print out the expressions from the block expression.
Console.WriteLine("The expressions from the block expression:");
foreach (var expr in blockExpr.Expressions)

Console.WriteLine("The result of executing the expression tree:");
// The following statement first creates an expression tree,
// then compiles it, and then executes it.

// This code example produces the following output:
// The expressions from the block expression:
// (sampleVar = 1)
// (sampleVar + 5)
// The result of executing the expression tree:
// 6

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