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Generating Code at Run Time With Reflection.Emit

Generating Code at Run Time With Reflection.Emit

Listing 1: The HelloReflectionEmit class

using System;
using System.Reflection;
using System.Reflection.Emit;

class HelloReflectionEmit
    static void Main()
        // Create a (weak) assembly name
        AssemblyName an = new AssemblyName();
        an.Name = "HelloReflectionEmit";

        // Define a new dynamic assembly (to be written to disk)
        AppDomain ad = AppDomain.CurrentDomain;
        AssemblyBuilder ab = 

        // Define a module for this assembly
        ModuleBuilder mb = ab.DefineDynamicModule(an.Name, 

        // namespace Foo { public class Bar { ... } }
        TypeBuilder tb = mb.DefineType("Foo.Bar", 

        // The leg bone's connected to the knee bone...
        MethodBuilder fb = tb.DefineMethod("Main", 
            new Type[] {typeof(string[])});

        // Write the ubiquitous "Hello, World!" method, in IL
        ILGenerator ilg = fb.GetILGenerator();

        ilg.Emit(OpCodes.Ldstr, "Hello, World!");
                new Type[] {typeof(string)} ));


        // Seal the lid on this type
        Type t = tb.CreateType();

        // Set the entrypoint (thereby declaring it an EXE)

        // Save it

        // Done!
        Console.WriteLine("File saved: {0}", "Hello.exe");

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