using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Reflection.Emit;
using System.Threading;
class Program
{
static void Main(string[] args)
{
AppDomain curAppDomain = Thread.GetDomain();
CreateMyAsm(curAppDomain);
Assembly a = Assembly.Load("MyAssembly");
Type hello = a.GetType("MyAssembly.HelloWorld");
string msg = "asdf";
object[] ctorArgs = new object[1];
ctorArgs[0] = msg;
object obj = Activator.CreateInstance(hello, ctorArgs);
MethodInfo mi = hello.GetMethod("SayHello");
mi.Invoke(obj, null);
mi = hello.GetMethod("GetMsg");
Console.WriteLine(mi.Invoke(obj, null));
}
public static void CreateMyAsm(AppDomain curAppDomain)
{
AssemblyName assemblyName = new AssemblyName();
assemblyName.Name = "MyAssembly";
assemblyName.Version = new Version("1.0.0.0");
AssemblyBuilder assembly =curAppDomain.DefineDynamicAssembly(assemblyName,AssemblyBuilderAccess.Save);
ModuleBuilder module = assembly.DefineDynamicModule("MyAssembly", "MyAssembly.dll");
TypeBuilder helloWorldClass = module.DefineType("MyAssembly.HelloWorld",TypeAttributes.Public);
FieldBuilder msgField = helloWorldClass.DefineField("theMessage", Type.GetType("System.String"),FieldAttributes.Private);
Type[] constructorArgs = new Type[1];
constructorArgs[0] = typeof(string);
ConstructorBuilder constructor = helloWorldClass.DefineConstructor(MethodAttributes.Public, CallingConventions.Standard, constructorArgs);
ILGenerator constructorIL = constructor.GetILGenerator();
constructorIL.Emit(OpCodes.Ldarg_0);
Type objectClass = typeof(object);
ConstructorInfo superConstructor = objectClass.GetConstructor(new Type[0]);
constructorIL.Emit(OpCodes.Call, superConstructor);
constructorIL.Emit(OpCodes.Ldarg_0);
constructorIL.Emit(OpCodes.Ldarg_1);
constructorIL.Emit(OpCodes.Stfld, msgField);
constructorIL.Emit(OpCodes.Ret);
helloWorldClass.DefineDefaultConstructor(MethodAttributes.Public);
MethodBuilder getMsgMethod = helloWorldClass.DefineMethod("GetMsg", MethodAttributes.Public, typeof(string), null);
ILGenerator methodIL = getMsgMethod.GetILGenerator();
methodIL.Emit(OpCodes.Ldarg_0);
methodIL.Emit(OpCodes.Ldfld, msgField);
methodIL.Emit(OpCodes.Ret);
MethodBuilder sayHiMethod = helloWorldClass.DefineMethod("SayHello", MethodAttributes.Public, null, null);
methodIL = sayHiMethod.GetILGenerator();
methodIL.EmitWriteLine("Hello!");
methodIL.Emit(OpCodes.Ret);
helloWorldClass.CreateType();
assembly.Save("MyAssembly.dll");
}
}