得到程序句柄并向他发送ctrl+c问题

得到程序句柄并向他发送ctrl+c，有时能获取，有时得点几次才能获取，前几次都是得到为空，都得到程序的焦点，但为什么得到的为空对象，再点一次也能获取，请高手指教问题在哪？ private void button1_Click(object sender, EventArgs e)
        {
            ParenthWnd =FindWindow(null, name);
            if (ParenthWnd != null)
            {
                if (!ParenthWnd.Equals(IntPtr.Zero))
                {
                    ShowWindow(ParenthWnd, 9);
                    SetForegroundWindow(ParenthWnd);
                    ShowWindow(ParenthWnd, 3);
                    SendKeys.SendWait("^c");
                    Thread.Sleep(100);
                    message = Convert.ToString(Clipboard.GetDataObject().GetData(DataFormats.Text));
                }
                if (!string.IsNullOrEmpty(message))
                {
                    SetForegroundWindow(this.Handle);
                    Thread th = new Thread(new ThreadStart(getexc));
                    th.Start();
                    Thread.Sleep(100);                }