win32 工具栏位置太低

Question

我刚刚学习 win32 ui，并从 Microsoft 文档中抓取了一个示例工具栏。当我运行这个简单的示例时，结果是工具栏太低。我不明白这是为什么。

这是我的代码：

#include <Windows.h>
#include <CommCtrl.h>
#include <cstdio>

HIMAGELIST g_hImageList = NULL;
const int IDM_NEW = 201;
const int IDM_OPEN = 202;
const int IDM_SAVE = 203;

HWND MainWindowToolbar( HWND Window )
{
    // Declare and initialize local constants.
    const int ImageListID    = 0;
    const int numButtons     = 3;
    const int bitmapSize     = 16;
    

    RECT MainWindowRect;
    GetClientRect(Window, &MainWindowRect);
    const DWORD buttonStyles = BTNS_AUTOSIZE;

    // Create the toolbar.
    HWND hWndToolbar = CreateWindowEx(0, TOOLBARCLASSNAME, NULL, 
                                      WS_CHILD | TBSTYLE_WRAPABLE, 0, 0, 0, 0, 
                                      Window, NULL, GetModuleHandle(NULL), NULL);
        
    if (hWndToolbar == NULL)
        return NULL;

    // Create the image list.
    g_hImageList = ImageList_Create(bitmapSize, bitmapSize,   // Dimensions of individual bitmaps.
                                    ILC_COLOR16 | ILC_MASK,   // Ensures transparent background.
                                    numButtons, 0);

    // Set the image list.
    SendMessage(hWndToolbar, TB_SETIMAGELIST, 
                (WPARAM)ImageListID, 
                (LPARAM)g_hImageList);

    // Load the button images.
    SendMessage(hWndToolbar, TB_LOADIMAGES, 
                (WPARAM)IDB_STD_SMALL_COLOR, 
                (LPARAM)HINST_COMMCTRL);

    // Initialize button info.
    // IDM_NEW, IDM_OPEN, and IDM_SAVE are application-defined command constants.
    
    TBBUTTON tbButtons[numButtons] = 
    {
        { MAKELONG(STD_FILENEW,  ImageListID), IDM_NEW,  TBSTATE_ENABLED, buttonStyles, {0}, 0, (INT_PTR)L"New" },
        { MAKELONG(STD_FILEOPEN, ImageListID), IDM_OPEN, TBSTATE_ENABLED, buttonStyles, {0}, 0, (INT_PTR)L"Open"},
        { MAKELONG(STD_FILESAVE, ImageListID), IDM_SAVE, 0,               buttonStyles, {0}, 0, (INT_PTR)L"Save"}
    };

    // Add buttons.
    SendMessage(hWndToolbar, TB_BUTTONSTRUCTSIZE, (WPARAM)sizeof(TBBUTTON), 0);
    SendMessage(hWndToolbar, TB_ADDBUTTONS,       (WPARAM)numButtons,       (LPARAM)&tbButtons);

    // Resize the toolbar, and then show it.
    SendMessage(hWndToolbar, TB_AUTOSIZE, 0, 0); 
    ShowWindow(hWndToolbar,  TRUE);
    
    return hWndToolbar;
}

HWND TreeViewHandle;
LRESULT CALLBACK MainWindowCallback(
    HWND Window,
    UINT Message,
    WPARAM WParam,
    LPARAM LParam
)
{
    LRESULT Result;
    switch(Message)
    {
        case WM_CREATE:
        {
            MainWindowToolbar( Window );
        } break;
        case WM_SIZE:
        {
            OutputDebugString("WM_SIZE\n");
        } break;
        case WM_DESTROY:
        {
            PostQuitMessage(0);
        } break;
        case WM_CLOSE:
        {
            OutputDebugString("WM_CLOSE\n");
        } break;
        case WM_ACTIVATEAPP:
        {
            OutputDebugString("WM_ACTIVATEAPP\n");
        } break;

        case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(Window, &ps);
            FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1));
            EndPaint(Window, &ps);

        } break;
    }

    return DefWindowProc(Window, Message, WParam, LParam);
}

int CALLBACK WinMain(
    HINSTANCE Instance,
    HINSTANCE PrevInstance,
    LPSTR     lpCmdLine,
    int       nShowCmd
)
{
    WNDCLASS WindowClass = {};
    WindowClass.style         = CS_HREDRAW | CS_VREDRAW;
    WindowClass.lpfnWndProc   = MainWindowCallback;
    WindowClass.hInstance     = Instance;
    WindowClass.lpszMenuName = "mainMenu";
    WindowClass.lpszClassName = "MainWindow";

    RegisterClass(&WindowClass);

    HWND Window = CreateWindowEx(
        0,
        WindowClass.lpszClassName,
        "Win32 Test App",
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        0,
        0,
        Instance,
        0
    );
    if (Window == nullptr)
    {
        printf("Error CreateWindow()\n");
        exit(1);
    }

    ShowWindow(Window, nShowCmd);

    MSG Message;
    while ( GetMessage(&Message, 0, 0, 0) > 0 )
    {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }
}

这大概就是它产生的结果。为什么 Windows 在工具栏上方留了这么多空间？

Answer 1

问题似乎是我没有从 WM_CREATE 或 WM_PAINT 消息返回 0，并且仍在调用 DefaultWindowProc()。

工作代码：

        case WM_CREATE:
           MainWindowToolbar( Window );
           return 0;

        case WM_PAINT:
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(Window, &ps);
            FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1));
            EndPaint(Window, &ps);
            return 0;