怎么用C#程序来区分键盘上的左右SHIFT键

// 可以用 msg.LParam 来区分左右 Alt, Ctrl, Shift, 两个Enter 键



using System.Windows.Forms;



class Test : Form

{

  protected override bool ProcessCmdKey(ref Message msg, Keys keyData)

  {

    string s = string.Empty;

    switch ((int)msg.LParam)

    {

      case 0x20380001 : s = "LAlt"    ; break;

      case 0x21380001 : s = "RAlt"    ; break;

      case 0x001d0001 : s = "LControl"; break;

      case 0x011d0001 : s = "RControl"; break;

      case 0x002a0001 : s = "LShift"  ; break;

      case 0x00360001 : s = "RShift"  ; break;

      case 0x001c0001 : s = "Enter"   ; break;

      case 0x011c0001 : s = "PadEnter"; break;

    }

    MessageBox.Show(msg + "\r\n" + keyData + "\r\n" + s);

    return base.ProcessCmdKey(ref msg, keyData);

  }



  static void Main()

  {

    Application.Run(new Test());

  }

}