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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.

System_CAPS_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 namespace System;
using namespace System::Reflection;
using namespace System::Reflection::Emit;

public ref class Test
{   
};

// Declare a delegate that will be used to execute the completed
// dynamic method.
delegate int HelloInvoker(String^ msg, int ret);

int 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.
    array<Type^>^ helloArgs = {String::typeid, int::typeid};

    // 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 = gcnew DynamicMethod("Hello", 
        int::typeid,
        helloArgs,
        Test::typeid->Module);

    // Create an array that specifies the parameter types of the
    // overload of Console.WriteLine to be used in Hello.
    array<Type^>^ writeStringArgs = {String::typeid};
    // Get the overload of Console.WriteLine that has one
    // String parameter.
    MethodInfo^ writeString =
        Console::typeid->GetMethod("WriteLine", writeStringArgs);

    // Get an ILGenerator and emit a body for the dynamic method.
    ILGenerator^ ilgen = hello->GetILGenerator();
    // Load the first argument, which is a string, onto the stack.
    ilgen->Emit(OpCodes::Ldarg_0);
    // Call the overload of Console.WriteLine that prints a string.
    ilgen->EmitCall(OpCodes::Call, writeString, nullptr);
    // The Hello method returns the value of the second argument;
    // to do this, load the onto the stack and return.
    ilgen->Emit(OpCodes::Ldarg_1);
    ilgen->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^ helloDelegate =
        (HelloInvoker^) hello->CreateDelegate(HelloInvoker::typeid);

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

    // Do it again, with different arguments.
    returnValue = helloDelegate("\r\nHi, Mom!", 5280);
    Console::WriteLine("helloDelegate(\"Hi, Mom!\", 5280) returned {0}",
        returnValue);

    // Create an array of arguments to use with the Invoke method.
    array<Object^>^ delegateArgs = {"\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^ returnValueObject = hello->Invoke(nullptr, delegateArgs);
    Console::WriteLine("hello.Invoke returned {0}", returnValueObject);
}

.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.1
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