FindWindow 返回值为0

                        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr FindWindow(string strClass, string strWindow);
                        IntPtr hh = FindWindow("Notepad", "");


            MessageBox.Show(hh.ToString());

用spy++看下，记事本的窗口类是不是叫Notepad。另外第二个参数传null，而不是""
也可以第一个null，第二个写窗口标题

 static CWnd* PASCAL FindWindow(
   LPCTSTR lpszClassName,
   LPCTSTR lpszWindowName 
);


Collapse imageParameters
lpszClassName
Points to a null-terminated string that specifies the window's class name (a WNDCLASS structure). If lpClassName is NULL, all class names match.

lpszWindowName
Points to a null-terminated string that specifies the window name (the window's title). If lpWindowName is NULL, all window names match.