CreateWindowEx失败，GetLastError返回0;(CreateWindowEx fails with GetLastError returning 0; DefWindowProc

CreateWindowEx失败，GetLastError返回0;(CreateWindowEx fails with GetLastError returning 0; DefWindowProc is called in WindowProc [closed])

我刚刚遇到问题，同时使用WinAPI创建了一个窗口，这让我感到非常尴尬。

对CreateWindowEx的调用失败，返回0.之后立即调用的GetLastError也返回0。

当我在DefWindowProc上设置断点时，我的调试器确认它正在被调用，因为它应该是。

我在下面列出了一个最小的例子。 为什么对CreateWindowEx的调用失败？

的WndProc

LRESULT CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) { switch (Msg) { case WM_DESTROY: PostQuitMessage(EXIT_SUCCESS); return 0; } // LRESULT WINAPI DefWindowProc(HWND, UINT, WPARAM, LPARAM); return DefWindowProc(hWnd, msg, lParam, wParam); }

对CreateWindowEX的调用

hWnd = CreateWindowEx( WS_EX_OVERLAPPEDWINDOW, // dwExStyle CLASS_NAME, // lpClassName WINDOW_NAME, // lpWindowName WS_OVERLAPPEDWINDOW, // dwStyle CW_USEDEFAULT, 0, // x, y CW_USEDEFAULT, 0, // width, height NULL, // hWndParent NULL, // hMenu hInstance, // hInstance NULL // lpParam ); if (NULL == hWnd) { //GetLastError(); return 1; }

I just had a problem, while creating a window with WinAPI, which took me an embarrassing long time to solve.

The call to CreateWindowEx failed, returning 0. GetLastError, called immediately afterwards, also returned 0.

When I set a breakpoint on DefWindowProc, my debugger confirmed that it was being called, as it should be.

I've included a minimal example below. Why is the call to CreateWindowEx failing?

WndProc

LRESULT CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) { switch (Msg) { case WM_DESTROY: PostQuitMessage(EXIT_SUCCESS); return 0; } // LRESULT WINAPI DefWindowProc(HWND, UINT, WPARAM, LPARAM); return DefWindowProc(hWnd, msg, lParam, wParam); }

The call to CreateWindowEX

hWnd = CreateWindowEx( WS_EX_OVERLAPPEDWINDOW, // dwExStyle CLASS_NAME, // lpClassName WINDOW_NAME, // lpWindowName WS_OVERLAPPEDWINDOW, // dwStyle CW_USEDEFAULT, 0, // x, y CW_USEDEFAULT, 0, // width, height NULL, // hWndParent NULL, // hMenu hInstance, // hInstance NULL // lpParam ); if (NULL == hWnd) { //GetLastError(); return 1; }

最满意答案

我不小心切换了传递给DefWindowProc的wParam和lParam值。

以正确的顺序给出函数参数解决了我的问题。

return DefWindowProc(hWnd, msg, wParam, lParam);

I accidentally switched the wParam and lParam values I was passing to DefWindowProc.

Giving the function arguments in the proper order solved my problem.

return DefWindowProc(hWnd, msg, wParam, lParam);