Windows 編程[15] – 菜單訊息: WM_COMMAND

本例:

點擊任一個功能表項目, 都會發出一個 WM_COMMAND 訊息, 訊息的 wParam 參數的低兩位就是標識功能表項目的那個整數!

本例使用的資源檔(TestRes.rc):

#define IDM_New   101#define IDM_Open  102#define IDM_Save  103#define IDM_Exit  104#define IDM_Cut   201#define IDM_Copy  202#define IDM_Paste 203#define IDM_About 301MyMenu1 MENUEX DISCARDABLEBEGIN  POPUP "&File"        ,65535  BEGIN    MENUITEM "&New"    ,IDM_New    MENUITEM "&Open"   ,IDM_Open    MENUITEM "&Save"   ,IDM_Save    MENUITEM SEPARATOR    MENUITEM "E&xit"   ,IDM_Exit  END  POPUP "&Edit"        ,65535  BEGIN    MENUITEM "Cu&t"    ,IDM_Cut    MENUITEM "&Copy"   ,IDM_Copy    MENUITEM "&Paste"  ,IDM_Paste  END  POPUP "&Help"        ,65535  BEGIN    MENUITEM "&About"  ,IDM_About  ENDEND

本例代碼檔案:

program Project1;{$R 'TestRes.res' 'TestRes.rc'}uses  Windows, Messages;{供 WM_COMMAND 訊息調用的自訂過程}procedure OnCommand(wParam: Integer);begin  case LoWord(wParam) of    101: MessageBox(0, 'is New',  '', 0);    102: MessageBox(0, 'is Open', '', 0);    103: MessageBox(0, 'is Save', '', 0);    104: MessageBox(0, 'is Exit', '', 0);  end;end;function WndProc(wnd: HWND; msg: UINT; wParam,lParam: Integer): Integer; stdcall;begin  Result := 0;  case msg of    WM_COMMAND : OnCommand(wParam);  {收到 WM_COMMAND 訊息後調用 OnCommand 過程}    WM_DESTROY : PostQuitMessage(0);  else    Result := DefWindowProc(wnd, msg, wParam, lParam);  end;end;function RegMyWndClass: Boolean;var  cls: TWndClass;begin  cls.style         := CS_HREDRAW or CS_VREDRAW;  cls.lpfnWndProc   := @WndProc;  cls.cbClsExtra    := 0;  cls.cbWndExtra    := 0;  cls.hInstance     := HInstance;  cls.hIcon         := 0;  cls.hCursor       := LoadCursor(0, IDC_ARROW);  cls.hbrBackground := HBRUSH(COLOR_WINDOW + 1);  cls.lpszMenuName  := 'MyMenu1';  cls.lpszClassName := 'MyWnd';  Result := RegisterClass(cls)  0;end;{程式入口}const  tit = 'New Form';  ws = WS_OVERLAPPEDWINDOW;  x = 100; y = 100; w = 300; h = 180;var  hWnd: THandle;  Msg : TMsg;begin  RegMyWndClass;  hWnd := CreateWindow('MyWnd', tit, ws, x, y, w, h, 0, 0, HInstance, nil);  ShowWindow(hWnd, SW_SHOWNORMAL);  UpdateWindow(hWnd);  while(GetMessage(Msg, 0, 0, 0)) do  begin    TranslateMessage(Msg);    DispatchMessage(Msg);  end;end.