把外部程序作为MDI窗口打开的奇怪有关问题

把外部程序作为MDI窗口打开的奇怪问题

C# code

        private void tsbMicroBlog_Click(object sender, EventArgs e)        {            const string filePath = @"I:\work\my.exe";//notepad.exe            Process p = Process.Start(filePath);            p.WaitForInputIdle();            SetParent(p.MainWindowHandle, this.Handle);         }        [DllImport("user32.dll")]        private static extern int SetParent(IntPtr hWndChild, IntPtr hWndNewParent);