Win32 API logic error: Code compiles fine but the main window doesn't show up

Question

我正在重写我写的一个软件，因为程序大小和性能问题；代码编译正常，但 window 没有显示。

我已经调查了其他关于此的问题，但 none 解决了我的问题，这就是为什么我要问一个新问题，为了完整起见，请解释代码有什么问题以及如何解决解决问题。

我使用的是 Visual Studio 2013。这是代码：

WFrame.h

#pragma once

#include <Windows.h>
#include <tchar.h>
#include <wchar.h>

class WFrame
{
public:
    WFrame();
    WFrame(LPCWSTR szClassName, LPCWSTR szWindowTitle, HINSTANCE hInstance, int nCmdShow, int nX, int nY, int nWidth, int nHeight, DWORD dwStyle = WS_EX_OVERLAPPEDWINDOW);
    ~WFrame();

    void show();

    static LRESULT CALLBACK staticWindowProcedure(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
    virtual LRESULT CALLBACK WindowProcedure(UINT uMsg, WPARAM wParam, LPARAM lParam);
protected:

private:
    HWND hWnd;
    int cmdShow;
};

WFrame.cpp

#include "WFrame.h"


WFrame::WFrame()
{

}

WFrame::WFrame(LPCWSTR szClassName, LPCWSTR szWindowTitle, HINSTANCE hInstance, int nCmdShow, int nX, int nY, int nWidth, int nHeight, DWORD dwStyle)
{
    WNDCLASSEX wClass;
    ZeroMemory(&wClass, sizeof(WNDCLASSEX));
    wClass.cbClsExtra = NULL;
    wClass.cbSize = sizeof(WNDCLASSEX);
    wClass.cbWndExtra = NULL;
    wClass.hbrBackground = (HBRUSH)COLOR_WINDOW;
    wClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wClass.hIcon = NULL;
    wClass.hIconSm = NULL;
    wClass.hInstance = hInstance;
    wClass.lpfnWndProc = (WNDPROC) WFrame::staticWindowProcedure;
    wClass.lpszClassName = szClassName;
    wClass.lpszMenuName = NULL;
    wClass.style = CS_HREDRAW | CS_VREDRAW;

    if (!RegisterClassEx(&wClass))
    {
        int nResult = GetLastError();
        MessageBox(NULL,
            L"Window class creation failed",
            L"Window Class Failed",
            MB_ICONERROR);
    }

    this->hWnd = CreateWindow(
        szClassName,
        szWindowTitle,
        dwStyle,
        nX,
        nY,
        nWidth,
        nHeight,
        NULL,
        NULL,
        hInstance,
        NULL);

    if (!hWnd)
    {
        int nResult = GetLastError();

        MessageBox(NULL,
            L"Window creation failed",
            L"Window Creation Failed",
            MB_ICONERROR);
    }

}

WFrame::~WFrame()
{
    delete this;
}

void WFrame::show()
{
    ShowWindow(this->hWnd, this->cmdShow);
    UpdateWindow(this->hWnd);
}

LRESULT CALLBACK WFrame::staticWindowProcedure(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    WFrame* winptr = (WFrame*)GetWindowLongPtr(hWnd, GWLP_USERDATA);

    if (winptr == NULL) {
        return DefWindowProc(hWnd, uMsg, wParam, lParam);
    }
    else {
        return winptr->WindowProcedure(uMsg, wParam, lParam);
    }
}

LRESULT CALLBACK WFrame::WindowProcedure(UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
        case WM_CLOSE:
            DestroyWindow(this->hWnd);
            break;
        case WM_DESTROY:
            if (!GetParent(this->hWnd))
                PostQuitMessage(0);
            break;
    }

    return DefWindowProc(this->hWnd, uMsg, wParam, lParam);
}

Main.cpp

#include <Windows.h>

#include "WFrame.h"

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WFrame * frame = new WFrame(L"Window", L"Window", hInstance, nCmdShow, 0, 0, 1024, 700);
    frame->show();

    MSG msg;
    ZeroMemory(&msg, sizeof(MSG));

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

    return msg.wParam;
}

感谢进一步的回答。

Answer 1

您正在使用 WS_EX_OVERLAPPEDWINDOW 作为 CreateWindow 的 dwStyle 参数。该标志实际上应该用于 CreateWindowEx 的 dwExStyle 参数。请改用 WS_OVERLAPPEDWINDOW。

完成后别忘了delete frame;。实际上，您在这里甚至不需要指针。只需在堆栈上实例化 frame。

此外，对于您处理的 window 条消息，您应该 return 0;，而不是调用 DefWindowProc。

Answer 2

我没有看到你给成员变量cmdShow赋值，所以它的默认值为0，也就是SW_HIDE，所以你应该试试下面的代码，看看window可以在 WFrame 初始值设定项中显示或分配 cmdShow。

void WFrame::show()
{
    ShowWindow(this->hWnd, SW_SHOW);
    UpdateWindow(this->hWnd);
}

Win32 API logic error: Code compiles fine but the main window doesn't show up

Win32 API logic error: Code compiles fine but the main window doesn't show up

c++

winapi