Windows 編程[16] – 添加與刪除功能表項目:GetMenu、AppendMenu、DeleteMenu、DrawMenuBar

本例:

本例在表單建立時, 動態添加了三個菜單; 並賦予它們自我刪除的功能.

本例使用的資源檔(TestRes.rc):

MyMenu1 MENUEXBEGIN  POPUP "&File"  BEGIN    MENUITEM "E&xit"  ,101  ENDEND

本例代碼檔案:

program Project1;{$R 'TestRes.res' 'TestRes.rc'}uses  Windows, Messages;const  IDM_1 = 1; {定義三個標識功能表項目的常量}  IDM_2 = 2;  IDM_3 = 3;{收到 WM_CREATE 訊息時添加三個功能表項目}procedure OnCreate(h: HWND);var  hm: HMENU;begin  hm := GetMenu(h);                            {擷取視窗主菜單控制代碼}  AppendMenu(hm, MFT_STRING, IDM_1, 'Menu&1'); {添加功能表項目}  AppendMenu(hm, MFT_STRING, IDM_2, 'Menu&2');  AppendMenu(hm, MFT_STRING, IDM_3, 'Menu&3');end;{收到 WM_COMMAND 訊息時需要做的工作}procedure OnCommand(h: HWND; wParam: Integer);var  w: Word;begin  w := LoWord(wParam);  case w of    101: DestroyWindow(h);          {關閉視窗; 101 是在資源檔中給 Exit 菜單指定的標識}    IDM_1, IDM_2, IDM_3: begin      {點擊建立的三個菜單時...}      DeleteMenu(GetMenu(h), w, 0); {刪除該菜單}      DrawMenuBar(h);               {重繪菜單}    end;  end;end;function WndProc(wnd: HWND; msg: UINT; wParam: Integer; lParam: Integer): Integer; stdcall;begin  Result := 0;  case msg of    WM_CREATE  : OnCreate(wnd);          {收到 WM_CREATE 訊息後調用 OnCreate 過程}    WM_COMMAND : OnCommand(wnd, 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.