hello, world... Reflection.Emit style!
Before I head home, I thought I'd post up your typical “Hello, World” style app in Reflection.Emit. ~20 lines of C# code, not too bad for code generation of a Console.WriteLine. For those who don't know what Reflection.Emit is, or what it can do, have a look here here and here for starters.
using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Threading;
public class EmitHelloWorld
{
static void Main(string[] args)
{
// create a dynamic assembly and module
AssemblyName assemblyName = new AssemblyName();
assemblyName.Name = "HelloWorld";
AssemblyBuilder assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.RunAndSave);
ModuleBuilder module;
module = assemblyBuilder.DefineDynamicModule("HelloWorld.exe");
// create a new type to hold our Main method
TypeBuilder typeBuilder = module.DefineType("HelloWorldType", TypeAttributes.Public | TypeAttributes.Class);
// create the Main(string[] args) method
MethodBuilder methodbuilder = typeBuilder.DefineMethod("Main", MethodAttributes.HideBySig | MethodAttributes.Static | MethodAttributes.Public, typeof(void), new Type[] { typeof(string[]) });
// generate the IL for the Main method
ILGenerator ilGenerator = methodbuilder.GetILGenerator();
ilGenerator.EmitWriteLine("hello, world");
ilGenerator.Emit(OpCodes.Ret);
// bake it
Type helloWorldType = typeBuilder.CreateType();
// run it
helloWorldType.GetMethod("Main").Invoke(null, new string[] {null});
// set the entry point for the application and save it
assemblyBuilder.SetEntryPoint(methodbuilder, PEFileKinds.ConsoleApplication);
assemblyBuilder.Save("HelloWorld.exe");
}
}