Compile Method
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Expression<TDelegate>.Compile Method

Compiles the lambda expression described by the expression tree into executable code and produces a delegate that represents the lambda expression.

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

public TDelegate Compile()

Return Value

Type: TDelegate
A delegate of type TDelegate that represents the compiled lambda expression described by the Expression<TDelegate>.

The Compile method produces a delegate of type TDelegate at runtime. When that delegate is executed, it has the behavior described by the semantics of the Expression<TDelegate>.

The Compile method can be used to obtain the value of any expression tree. First, create a lambda expression that has the expression as its body by using the Lambda method. Then call Compile to obtain a delegate, and execute the delegate to obtain the value of the expression.

The following code example demonstrates how Compile is used to execute an expression tree.

            // Lambda expression as data in the form of an expression tree.
            System.Linq.Expressions.Expression<Func<int, bool>> expr = i => i < 5;
            // Compile the expression tree into executable code.
            Func<int, bool> deleg = expr.Compile();
            // Invoke the method and print the output.
            Console.WriteLine("deleg(4) = {0}", deleg(4));

            /*  This code produces the following output:

                deleg(4) = True

.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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