Windows 编程[16] - 添加与删除菜单项:GetMenu、AppendMenu、DeleteMenu、DrawMenuBar

本例效果图:

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本例在窗体建立时, 动态添加了三个菜单; 并赋予它们自我删除的功能.

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本例使用的资源文件(TestRes.rc):

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MyMenu1 MENUEX

BEGIN

  POPUP "&File"

  BEGIN

    MENUITEM "E&xit"  ,101

  END

END


 
   

本例代码文件:

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program Project1;



{$R 'TestRes.res' 'TestRes.rc'}



uses

  Windows, Messages;



const

  IDM_1 = 1; {定义三个标识菜单项的常量}

  IDM_2 = 2;

  IDM_3 = 3;



{收到 WM_CREATE 消息时添加三个菜单项}

procedure OnCreate(h: HWND);

var

  hm: HMENU;

begin

  hm := GetMenu(h);                            {获取窗口主菜单句柄}

  AppendMenu(hm, MFT_STRING, IDM_1, 'Menu&1'); {添加菜单项}

  AppendMenu(hm, MFT_STRING, IDM_2, 'Menu&2');

  AppendMenu(hm, MFT_STRING, IDM_3, 'Menu&3');

end;



{收到 WM_COMMAND 消息时需要做的工作}

procedure OnCommand(h: HWND; wParam: Integer);

var

  w: Word;

begin

  w := LoWord(wParam);

  case w of

    101: DestroyWindow(h);          {关闭窗口; 101 是在资源文件中给 Exit 菜单指定的标识}

    IDM_1, IDM_2, IDM_3: begin      {点击新建的三个菜单时...}

      DeleteMenu(GetMenu(h), w, 0); {删除该菜单}

      DrawMenuBar(h);               {重绘菜单}

    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 消息后调用 OnCreate 过程}

    WM_COMMAND : OnCommand(wnd, wParam); {收到 WM_COMMAND 消息后调用 OnCommand 过程}

    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;



{程序入口}

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.