//引入命名空间
using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Security.Permissions;

public class CodeGenerator
{
   AssemblyBuilder myAssemblyBuilder;
   public CodeGenerator()
   {
      // Get the current application domain for the current thread.
      AppDomain myCurrentDomain = AppDomain.CurrentDomain;
      AssemblyName myAssemblyName = new AssemblyName();
      myAssemblyName.Name = "TempAssembly";

      // Define a dynamic assembly in the current application domain.
      myAssemblyBuilder = myCurrentDomain.DefineDynamicAssembly
                     (myAssemblyName, AssemblyBuilderAccess.Run);

      // Define a dynamic module in this assembly.
      ModuleBuilder myModuleBuilder = myAssemblyBuilder.
                                      DefineDynamicModule("TempModule");

      // Define a runtime class with specified name and attributes.
      TypeBuilder myTypeBuilder = myModuleBuilder.DefineType
                                       ("TempClass",TypeAttributes.Public);

      // Add 'Greeting' field to the class, with the specified attribute and type.
      FieldBuilder greetingField = myTypeBuilder.DefineField("Greeting", 
                                                            typeof(String), FieldAttributes.Public);
      Type[] myMethodArgs = { typeof(String) };

      // Add 'MyMethod' method to the class, with the specified attribute and signature.
      MethodBuilder myMethod = myTypeBuilder.DefineMethod("MyMethod",
         MethodAttributes.Public, CallingConventions.Standard, null,myMethodArgs);

      ILGenerator methodIL = myMethod.GetILGenerator();
      methodIL.EmitWriteLine("In the method...");
      methodIL.Emit(OpCodes.Ldarg_0);
      methodIL.Emit(OpCodes.Ldarg_1);
      methodIL.Emit(OpCodes.Stfld, greetingField);
      methodIL.Emit(OpCodes.Ret);
      myTypeBuilder.CreateType();
   }
   public AssemblyBuilder MyAssembly
   {
      get
      {
         return this.myAssemblyBuilder;
      }
   }
}
public class TestClass
{
   [PermissionSetAttribute(SecurityAction.Demand, Name="FullTrust")]
   public static void Main()
   {
      CodeGenerator myCodeGenerator = new CodeGenerator();
      // Get the assembly builder for 'myCodeGenerator' object.
      AssemblyBuilder myAssemblyBuilder = myCodeGenerator.MyAssembly;
      // Get the module builder for the above assembly builder object .
      ModuleBuilder myModuleBuilder = myAssemblyBuilder.
                                                           GetDynamicModule("TempModule");
      Console.WriteLine("The fully qualified name and path to this "
                               + "module is :" +myModuleBuilder.FullyQualifiedName);
      Type myType = myModuleBuilder.GetType("TempClass");
      MethodInfo myMethodInfo = 
                                                myType.GetMethod("MyMethod");
       // Get the token used to identify the method within this module.
      MethodToken myMethodToken = 
                        myModuleBuilder.GetMethodToken(myMethodInfo);
      Console.WriteLine("Token used to identify the method of 'myType'"
                    + " within the module is {0:x}",myMethodToken.Token);
     object[] args={"Hello."};
     object myObject = Activator.CreateInstance(myType,null,null);
     myMethodInfo.Invoke(myObject,args);
   }
}