在 winapi 中选择按钮会导致其他功能中断

Question

我正在用 Win32 API 编写应用程序。布局基本上由一个永远不变的左 window 和一个在两个 windows 之间变化的右 window 组成。为了控制这个变化，我使用 ShowWindow(hWnd, SW_SHOW/SW_HIDE).

在左侧window，有一个显示一个window并隐藏另一个的按钮。我还有显示和隐藏 window.

的键盘输入

在我单击按钮之前，键盘功能工作正常。单击按钮后，按键将停止工作。

起初我以为这是因为按钮不同window；然而，当我试图捕捉 child window 中的按键输入时，没有任何反应。

这是一个最小的可重现示例，它只有一个按钮和一个 child window。请注意，单击 Shift/Tab 会导致 child window 变为 appear/disappear。单击该按钮会使 child 消失一次，但它似乎也禁用了按键输入。即使在按钮外部单击，child 也不会恢复它们。

可能是什么问题？

//libraries
#pragma comment ("lib", "Comctl32.lib")
#pragma comment ("lib", "d2d1.lib")


#define WIN32_LEAN_AND_MEAN             // Exclude rarely-used stuff from Windows headers
// Windows Header Files
#include <windows.h>
// C RunTime Header Files

#include <vector>
#include <string>


#define IDS_APP_TITLE           103
#define IDI_PRACTICE            107
#define IDI_SMALL               108
#define IDC_PRACTICE            109

#define IDC_BUTTON              101
#define MAX_LOADSTRING          100




// Global Variables:
HINSTANCE hInst;                                // current instance
WCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name




LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK WndProcChild(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

ATOM MyRegisterClass(HINSTANCE hInstance);

HWND childHWND;

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow);

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
    _In_opt_ HINSTANCE hPrevInstance,
    _In_ LPWSTR    lpCmdLine,
    _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);
    // Initialize global strings
    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadStringW(hInstance, IDC_PRACTICE, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    SetProcessDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);

    // Perform application initialization:
    if (!InitInstance(hInstance, nCmdShow))
    {
        return FALSE;
    }
    HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_PRACTICE));
    MSG msg;
    // Main message loop:
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
    return (int)msg.wParam;
}


LRESULT CALLBACK WndProcChild(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    return DefWindowProc(hWnd, message, wParam, lParam);
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{  
    switch (message)
    {
    case WM_CREATE:
    {
        HWND button = CreateWindowW(L"button", L"Hide", WS_CHILD | WS_VISIBLE, 100, 100, 200, 100, hWnd, (HMENU)IDC_BUTTON, hInst, nullptr);
        break;
    }
    case WM_COMMAND:
    {
        int wmld = LOWORD(wParam);

        switch (wmld)
        {
        case IDC_BUTTON:
            ShowWindow(childHWND, SW_HIDE);
            break;
        }
        break;
    }
    case WM_DESTROY:
        PostQuitMessage(0);
        break;

    case WM_KEYDOWN:
        switch (wParam)
        {
        case VK_SHIFT:
            ShowWindow(childHWND, SW_HIDE);

            break;
        case VK_TAB:
            ShowWindow(childHWND, SW_SHOW);

            break;
        }
        break;

    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
    
}

ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_PRACTICE));
    wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground = (HBRUSH)(GetStockObject(WHITE_BRUSH));
    wcex.lpszMenuName = MAKEINTRESOURCEW(IDC_PRACTICE);
    wcex.lpszClassName = L"Parent";
    wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
    

    //Child wnd class
    WNDCLASSEXW wcexChild;
    wcexChild.cbSize = sizeof(WNDCLASSEX);
    wcexChild.style = CS_HREDRAW | CS_VREDRAW;
    wcexChild.lpfnWndProc = WndProcChild;
    wcexChild.cbClsExtra = 0;
    wcexChild.cbWndExtra = 0;
    wcexChild.hInstance = hInstance;
    wcexChild.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_PRACTICE));
    wcexChild.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wcexChild.hbrBackground = (HBRUSH)(GetStockObject(BLACK_BRUSH));
    wcexChild.lpszMenuName = MAKEINTRESOURCEW(IDC_PRACTICE);
    wcexChild.lpszClassName = L"Child";
    wcexChild.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
    return RegisterClassExW(&wcexChild) && RegisterClassExW(&wcex);
}


BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
    hInst = hInstance; // Store instance handle in our global variable
    HWND hWnd = CreateWindowW(L"Parent", L"PARENT", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, nullptr, nullptr, hInstance, nullptr);

    childHWND = CreateWindowW(L"Child", szTitle, WS_CHILD | WS_VISIBLE,
        500, 500, 500, 500, hWnd, nullptr, hInstance, nullptr);

    if (!hWnd)
    {
        return FALSE;
    }
    ShowWindow(childHWND, nCmdShow);
    UpdateWindow(childHWND);

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);
    return TRUE;
}

Answer 1

您正在主 window 的 WndProc 中处理键盘消息，因此您的 window 只有在具有输入焦点时才会接收键盘消息。当您单击按钮时，它接收输入焦点，因此后续的键盘消息将改为发送到按钮的 WndProc。因此，您必须将按钮子类化以拦截发送给它的键盘消息，或者在发送它们之前直接在消息循环中处理键盘消息。

Answer 2

当您按下一个按钮时，焦点将位于该按钮上，只有主要 window 处理键盘击键。

您有一个简单的方法来调整焦点 window，方法是调用 SetFocus:

    case IDC_BUTTON:
        ShowWindow(childHWND, SW_HIDE);
        SetFocus(hWnd);
        break;

当然可以像Remy说的那样，可以通过SetWindowSubclass对按钮进行子类化，然后通过处理键盘消息来处理键盘消息，或者修改焦点等方法

在 winapi 中选择按钮会导致其他功能中断

Selecting button in winapi causes other functionality to break

c++

windows

winapi

button

window