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DynamicMethod.GetILGenerator Method

Returns a Microsoft intermediate language (MSIL) generator for the method with a default MSIL stream size of 64 bytes.

Namespace:  System.Reflection.Emit
Assembly:  mscorlib (in mscorlib.dll)

public ILGenerator GetILGenerator()

Return Value

Type: System.Reflection.Emit.ILGenerator
An ILGenerator object for the method.

After a dynamic method has been completed, by calling the CreateDelegate or Invoke method, any further attempt to add MSIL is ignored. No exception is thrown.

NoteNote

There are restrictions on unverifiable code in dynamic methods, even in some full-trust scenarios. See the "Verification" section in Remarks for DynamicMethod.

The following code example creates a dynamic method that takes two parameters. The example emits a simple function body that prints the first parameter to the console, and the example uses the second parameter as the return value of the method. The example completes the method by creating a delegate, invokes the delegate with different parameters, and finally invokes the dynamic method using the Invoke method.

using System;
using System.Reflection;
using System.Reflection.Emit;
using Microsoft.VisualBasic;

public class Test
{
    // Declare a delegate that will be used to execute the completed 
    // dynamic method.  
    private delegate int HelloInvoker(string msg, int ret);

    public static void Main()
    {
        // Create an array that specifies the types of the parameters 
        // of the dynamic method. This method has a string parameter 
        // and an int parameter.
        Type[] helloArgs = {typeof(string), typeof(int)};

        // Create a dynamic method with the name "Hello", a return type
        // of int, and two parameters whose types are specified by the 
        // array helloArgs. Create the method in the module that 
        // defines the Test class.
        DynamicMethod hello = new DynamicMethod("Hello", 
            typeof(int), 
            helloArgs, 
            typeof(Test).Module);

        // Create an array that specifies the parameter types of the 
        // overload of Console.WriteLine to be used in Hello.
        Type[] writeStringArgs = {typeof(string)};
        // Get the overload of Console.WriteLine that has one 
        // String parameter.
        MethodInfo writeString = 
            typeof(Console).GetMethod("WriteLine", writeStringArgs);

        // Get an ILGenerator and emit a body for the dynamic method.
        ILGenerator il = hello.GetILGenerator();
        // Load the first argument, which is a string, onto the stack.
        il.Emit(OpCodes.Ldarg_0);
        // Call the overload of Console.WriteLine that prints a string.
        il.EmitCall(OpCodes.Call, writeString, null);
        // The Hello method returns the value of the second argument; 
        // to do this, load the onto the stack and return.
        il.Emit(OpCodes.Ldarg_1);
        il.Emit(OpCodes.Ret);

        // Create a delegate that represents the dynamic method. This 
        // action completes the method, and any further attempts to 
        // change the method will cause an exception.
        HelloInvoker hi = 
            (HelloInvoker) hello.CreateDelegate(typeof(HelloInvoker));

        // Use the delegate to execute the dynamic method. Save and 
        // print the return value. 
        int retval = hi("\r\nHello, World!", 42);
        Console.WriteLine("Executing delegate hi(\"Hello, World!\", 42) returned {0}",
            retval);

        // Do it again, with different arguments.
        retval = hi("\r\nHi, Mom!", 5280);
        Console.WriteLine("Executing delegate hi(\"Hi, Mom!\", 5280) returned {0}",
            retval);

        // Create an array of arguments to use with the Invoke method. 
        object[] invokeArgs = {"\r\nHello, World!", 42};
        // Invoke the dynamic method using the arguments. This is much 
        // slower than using the delegate, because you must create an 
        // array to contain the arguments, and ValueType arguments 
        // must be boxed. 
        object objRet = hello.Invoke(null, invokeArgs);
        Console.WriteLine("hello.Invoke returned {0}", objRet);
    }
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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