为对话框启用关闭按钮 c++ winapi

Question

有简单的窗口，打开对话框的按钮。但我想为其添加关闭按钮。

我尝试通过添加 WM_SYSMENU 添加关闭按钮，添加 EnableMenuItem，但它不起作用：

最少的代码是：
资源.rc：

IDD_FORMVIEW DIALOGEX 0, 0, 178, 86
STYLE DS_SETFONT | DS_CONTROL | WS_VISIBLE | WS_SYSMENU
EXSTYLE WS_EX_OVERLAPPEDWINDOW
CAPTION "TEST"
FONT 12, "Microsoft Sans Serif", 400, 0, 0xCC
BEGIN
    CTEXT           "Test",IDC_STATIC,46,4,74,8,0,WS_EX_CLIENTEDGE
END

resource.h:

#define IDD_FORMVIEW                    101

Test.cpp：

hwndButton = CreateWindowW(L"BUTTON",
            L"ENTER",
            WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON | WS_CLIPSIBLINGS,
            605, 510, 255, 45,
            hWnd, (HMENU)1, NULL, NULL);
case WM_COMMAND:
    {
        switch (LOWORD(wParam)) {


case 2: {
        if (hwndHTDW == NULL) {

hwndHTDW = CreateDialog(hInstance, MAKEINTRESOURCE(IDD_FORMVIEW), hWnd, DialogProc);    

ShowWindow(hwndHTDW, SW_SHOW);
UpdateWindow(hwndHTDW);
}
}
break;
        }
}

{


    switch (msg) {
    case WM_INITDIALOG: {
        EnableMenuItem(GetSystemMenu(hwnd, FALSE), SC_CLOSE,
            MF_BYCOMMAND | MF_ENABLED);

        return TRUE;
    }
        break;


    default:
        return FALSE;

    }

    return TRUE;

Answer 1

稍微修改一下你的代码。

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   hInst = hInstance; // Store instance handle in our global variable

   HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);
   hwndButton = CreateWindowW(L"BUTTON",
       L"ENTER",
       WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON | WS_CLIPSIBLINGS,
       605, 510, 255, 45,
       hWnd, (HMENU)1, NULL, NULL);
   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_COMMAND:
        {
            int wmId = LOWORD(wParam);
            // Parse the menu selections:
            switch (wmId)
            {
            case IDM_ABOUT:
                DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                break;
            case IDM_EXIT:
                DestroyWindow(hWnd);
                break;
            case 1: 
            {
                if (hwndHTDW == NULL) 
                {

                    hwndHTDW = CreateDialog(hInst, MAKEINTRESOURCE(IDD_FORMVIEW), hWnd, DialogProc);
                    Button_Close = CreateWindowW(L"BUTTON",
                        L"CLOSE",
                        WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON | WS_CLIPSIBLINGS | WS_TABSTOP,
                        130, 100, 80, 30,
                        hwndHTDW, (HMENU)2, NULL, NULL);
                    ShowWindow(hwndHTDW, SW_SHOW);
                    UpdateWindow(hwndHTDW);
                }
            }
            break;
            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
            }
        }
        break;
    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
            // TODO: Add any drawing code that uses hdc here...
            EndPaint(hWnd, &ps);
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

BOOL CALLBACK DialogProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    BOOL fError;

    switch (message)
    {
    case WM_INITDIALOG:
    {
        EnableMenuItem(GetSystemMenu(hwnd, FALSE), SC_CLOSE,
            MF_BYCOMMAND | MF_ENABLED);

        return TRUE;
    }
    break;

    case WM_COMMAND:
    {
        switch (LOWORD(wParam))
        {
        case 2:
        {
            EndDialog(hwnd, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        default:
            break;
        }
    }
    default:
        return FALSE;
    }
    return TRUE;
}

更新：

通过CreateWindow创建一个额外的按钮，并将对话框的句柄作为参数传递给按钮。

HWND Button_Close = CreateWindowW(L"BUTTON",
                        L"CLOSE",
                        WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON | WS_CLIPSIBLINGS | WS_TABSTOP,
                        130, 100, 80, 30,
                        hwndHTDW, (HMENU)2, NULL, NULL);

在对话框的回调函数中，添加WM_COMMAND事件并添加如下代码。

case WM_COMMAND:
{
    switch (LOWORD(wParam))
    {
    case 2:
    {
        EndDialog(hwnd, LOWORD(wParam));
        return (INT_PTR)TRUE;
    }
}