class Program 
   { 
       static void Main(string[] args) 
       { 
           Console.WriteLine("破浪Blog：http://www.cnblogs.com/whitewolf/"); 
       } 
   }

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using Mono.Cecil; 
using Mono.Cecil.Cil;

namespace BlogSample 
{ 
    class Program 
    { 
        static void Main(string[] args) 
        { 
            AssemblyDefinition assembiy = AssemblyFactory.GetAssembly(args[0]); 
            foreach (Mono.Cecil.TypeDefinition item in assembiy.MainModule.Types) 
            { 
                foreach (MethodDefinition method in item.Methods) 
                { 
                    if (method.Name.Equals("Main")) 
                    {

var ins = method.Body.Instructions[0]; 
                        var worker = method.Body.CilWorker; 
                        worker.InsertBefore(ins, worker.Create(OpCodes.Ldstr, "Method start…")); 
                        worker.InsertBefore(ins, worker.Create(OpCodes.Call, 
                            assembiy.MainModule.Import(typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) })))); 
                        ins = method.Body.Instructions[method.Body.Instructions.Count - 1];

worker.InsertBefore(ins, worker.Create(OpCodes.Ldstr, "Method finish…")); 
                        worker.InsertBefore(ins, worker.Create(OpCodes.Call, 
                            assembiy.MainModule.Import(typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) })))); 
                        break; 
                    } 
                }

}

AssemblyFactory.SaveAssembly(assembiy, "IL_" + args[0]); 
            Console.Read(); 
        } 
    } 
}