Question

我正在制作一个简单的Windows方案,但出于某种原因,登记中心正在归还FLSE,我不肯定为什么。

I set the lpszClassName,hInstance, and lpfnWndProc members of my WNDCLASS structure.

我的守则是:


#include <windows.h>
#include <tchar.h>

template<typename T>
class BaseWindow {
public:
    static LRESULT CALLBACK WndProc(HWND hwnd, UINT umsg, WPARAM wparam, LPARAM lparam) {
        T* pThis = NULL;
        if (umsg == WM_NCCREATE) {
            CREATESTRUCT* pCreate = (CREATESTRUCT*)lparam;
            pThis = (T*)pCreate->lpCreateParams;
            SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR)pThis);
            pThis->m_hwnd = hwnd;
        } else {
            pThis = (T*)GetWindowLongPtr(hwnd, GWLP_USERDATA);
        }
        return pThis->HandleMessage(umsg, wparam, lparam);
    }
    HWND m_hwnd;
    BOOL cls_state = FALSE;
    BOOL Init() {
        WNDCLASS wc;
        wc.lpszClassName = ClassName();
        wc.hInstance = GetModuleHandle(NULL);
        wc.lpfnWndProc = T::WndProc;

        return RegisterClass(&wc);

    }
    HWND Create(const char* szWindowName, DWORD dwStyle) {
        if (cls_state == FALSE) {
            if (!Init()) {
                MessageBox(NULL, _T("Init Failed. :("), _T("Error!"), MB_OK);
            }
            cls_state = TRUE;
        }
        return m_hwnd = CreateWindow(ClassName(), szWindowName, dwStyle, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, GetModuleHandle(NULL), this);
    }
    const char* ClassName() { return _T("BaseWindow Class"); }
};

class MainWindow : public BaseWindow<MainWindow> {
public:
    LRESULT HandleMessage(UINT uMsg, WPARAM wParam, LPARAM lParam) {
        return DefWindowProc(m_hwnd, uMsg, wParam, lParam);
    }
    const char* ClassName() { return _T("MainWindow Class"); }
};

int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nCmdShow) {


    MainWindow win;
    win.Create(_T("Mush!"), 0);

    ShowWindow(win.m_hwnd, nCmdShow);

    MSG msg;

    while (GetMessage (&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

Answer 1

贵国法典存在许多问题:

页: 1 页: 1

。

因此,没有田地被排除在外。在Win32的APIC中,有时是建筑领域是选择性的(如果是,它们就有相应的记载),但通常不是。这当然与<代码>有关。 WNDCLASS。有许多<代码>。 WNDCLASS 页: 1
<>RegisterClass(>>> 不能随附<>ERROR_INVALID_WINDOW_HANDLE,作为你的要求——但CreateWindow()。如果你认为是<代码>RegisterClass()报告错误,那么你可能会在错误的地方打上Get LastError((但你没有表明在你的代码中)。

注:WM_NCCREATE>:not第1条信息,即窗口可以接收,因此,<代码>WndProc(需要处理p>的可能性该仍可改为NUL。页: 1 This;HandleMessage(),从而导致未界定的行为<>。在此情况下,你可能会通过一个无效的<代码>HWND至DefWindowProc(,从而导致其失败,从而导致CreateWindow(>。
页: 1
页: 1 这是非法的。您需要将<条码>lpCreateParams投到您授予的<条码>。

<编码>p (T*) (BaseWindow*) pCreate->lpCreateParams;
页: 1

With that said, try this instead:

#include <windows.h>
#include <tchar.h>
#include <stdexcept>
#include <string>

template<typename T>
class BaseWindow {
public:
    static LRESULT CALLBACK WndProc(HWND hwnd, UINT umsg, WPARAM wparam, LPARAM lparam) {
        T* pThis;
        if (umsg == WM_NCCREATE) {
            CREATESTRUCT* pCreate = reinterpret_cast<CREATESTRUCT*>(lparam);
            pThis = static_cast<T*>(static_cast<BaseWindow*>(pCreate->lpCreateParams));
            SetWindowLongPtr(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(pThis));
            pThis->m_hwnd = hwnd;
        } else {
            pThis = reinterpret_cast<T*>(GetWindowLongPtr(hwnd, GWLP_USERDATA));
        }
        if (pThis) return pThis->HandleMessage(umsg, wparam, lparam);
        return DefWindowProc(hwnd, uMsg, wParam, lParam);
    }

    HWND m_hwnd = nullptr;
    bool cls_state = false;

    void Init() {
        WNDCLASS wc = {};
        wc.lpszClassName = ClassName();
        wc.hInstance = GetModuleHandle(nullptr);
        wc.lpfnWndProc = T::WndProc;

        if (!RegisterClass(&wc)) {
            DWORD err = GetLastError();
            if (err != ERROR_CLASS_ALREADY_EXISTS) {
                throw std::runtime_error("Init Failed, Error " + std::to_string(err));
            }
        }
    }

    HWND Create(const TCHAR* szWindowName, DWORD dwStyle) {
        if (!cls_state) {
            Init();
            cls_state = true;
        }
        m_hwnd = CreateWindow(ClassName(), szWindowName, dwStyle, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, nullptr, nullptr, GetModuleHandle(nullptr), this);
        if (!m_hwnd) {
            DWORD err = GetLastError();
            throw std::runtime_error("Create Failed, Error " + std::to_string(err));
        }
        return m_hwnd;
    }

    virtual const TCHAR* ClassName() { return _T("BaseWindow Class"); }
};

class MainWindow : public BaseWindow<MainWindow> {
public:
    LRESULT HandleMessage(UINT uMsg, WPARAM wParam, LPARAM lParam) {
        return DefWindowProc(m_hwnd, uMsg, wParam, lParam);
    }

    const TCHAR* ClassName() override { return _T("MainWindow Class"); }
};

int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nCmdShow) {
    try {
        MainWindow win;
        win.Create(_T("Mush!"), 0);

        ShowWindow(win.m_hwnd, nCmdShow);

        MSG msg;
        while (GetMessage (&msg, nullptr, 0, 0)) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }

        return msg.wParam;
    }
    catch (const std::exception& ex) {
        MessageBoxA(NULL, ex.what(), "Error!", MB_OK);
        return 0;
    }
}

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