c#으로 카톡보내는 프로그램 만들고있는데 왜안될까

[익명(59.17)]

using System;

using System.Diagnostics;

using System.Runtime.InteropServices;

using System.Threading;

namespace kakaobot_console

{

    class Program

    {

        [DllImport("user32.dll")]

        public static extern int FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll")]

        public static extern int FindWindowEx(int hWnd1, int hWnd2, string lpsz1, string lpsz2);

        [DllImport("user32.dll")]

        public static extern int SendMessage(int hwnd, int wMsg, int wParam, string lParam);

        [DllImport("user32.dll")]

        public static extern uint PostMessage(int hwnd, int wMsg, int wParam, int lParam);

        static void Main(string[] args)

        {

            int hd01 = FindWindow(null, "나");

            int hd03 = FindWindowEx(hd01, 0, "RichEdit20W", "");

            SendMessage(hd03, 0x000c, 0, "test");

            PostMessage(hd03, 0x0100, 0xD, 0x1C001);

        }

    }

}

카톡 봇 만들어보고 싶어서 구글링해보다가

그나마 알고있는 c#으로 된 코드찾아서 실행해봤더니 안됨

뭐가문제일까요