Winform 多组合老板键Alt_Ctrl_Shift

public  delegate  void HotkeyEventHandler( int HotKeyID);

     public  class SystemHotKey : System.Windows.Forms.IMessageFilter
    {
        List<UInt32> keyIDs =  new List<UInt32>();
        IntPtr hWnd;

         public  event HotkeyEventHandler OnHotkey;

         public  enum KeyFlags
        {
            Alt =  0x1,
            Ctrl =  0x2,
            Shift =  0x4,
            Win =  0x8,
             // 组合键等于值相加
            Alt_Ctrl =  0x3,
            Alt_Shift =  0x5,
            Ctrl_Shift =  0x6,
            Alt_Ctrl_Shift =  0x7
        }
        [DllImport( " user32.dll ")]
         public  static  extern UInt32 RegisterHotKey(IntPtr hWnd, UInt32 id, UInt32 fsModifiers, UInt32 vk);

        [DllImport( " user32.dll ")]
         public  static  extern UInt32 UnregisterHotKey(IntPtr hWnd, UInt32 id);

        [DllImport( " kernel32.dll ")]
         public  static  extern UInt32 GlobalAddAtom(String lpString);

        [DllImport( " kernel32.dll ")]
         public  static  extern UInt32 GlobalDeleteAtom(UInt32 nAtom);

         public SystemHotKey(IntPtr hWnd)
        {
             this.hWnd = hWnd;
        }

         public  int RegisterHotkey(KeyFlags keyflags, System.Windows.Forms.Keys Key)
        {
            System.Windows.Forms.Application.AddMessageFilter( this);
            UInt32 hotkeyid = GlobalAddAtom(System.Guid.NewGuid().ToString());
            RegisterHotKey((IntPtr)hWnd, hotkeyid, (UInt32)keyflags, (UInt32)Key);
            keyIDs.Add(hotkeyid);
             return ( int)hotkeyid;
        }

         public  void UnregisterHotkeys()
        {
             if (keyIDs.Count >  0)
            {

                System.Windows.Forms.Application.RemoveMessageFilter( this);
                 foreach (UInt32 key  in keyIDs)
                {
                    UnregisterHotKey(hWnd, key);
                    GlobalDeleteAtom(key);
                }
                keyIDs.Clear();
            }
        }

         public  bool PreFilterMessage( ref   System.Windows.Forms.Message m)
        {
             if (m.Msg ==  0x312)
            {
                 if (OnHotkey !=  null)
                {
                     foreach (UInt32 key  in keyIDs)
                    {
                         if ((UInt32)m.WParam == key)
                        {
                            OnHotkey(( int)m.WParam);
                             return  true;
                        }
                    }
                }
            }
             return  false;
        }
    }