window编程创建窗口失败

ww1724

错误是creatwindow无法读取内存,但是getlasterror得到0说明没错误,代码如下求助各位大佬
#include<windows.h>

LRESULT CALLBACK windowproc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hinstance,HINSTANCE Hinstance ,LPSTR lpCmdLine , int cmdshow ) {
        const WCHAR *class_name = L"simple class name";
        unsigned s;
        WNDCLASS wndclass = {NULL};
        wndclass.lpfnWndProc = windowproc;
        wndclass.hInstance = hinstance;
        wndclass.lpszClassName = class_name;
        RegisterClass(&wndclass);

               
        HWND windowhwnd = CreateWindowEx(1, class_name, L"first windows window", WS_TILEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hinstance, NULL);
        {
                s = GetLastError();
                MessageBox(NULL, L"创建窗口失败", L"错误提示", MB_OK);
        }
        ShowWindow(windowhwnd, cmdshow);
        return 0;
}


LRESULT CALLBACK windowproc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
        return LRESULT();

}

Debug

楼主这个代码范了几个致命的错误啊：
1、HWND windowhwnd = CreateWindowEx(...); 之后，并没有加 if 判断啊，直接就用一个大括号里面马上就 GetLastError 和 MessageBox 了，所以不管 CreateWindowEx 返回的 windowhwnd 是否成功，都会走 MessageBox；

2、窗口函数中直接 return LRESULT(); 了，应该 return DefWindowProc(hwnd, uMsg, wParam, lParam); 才对！

3、消息循环哪去了？没有消息循环，窗口即使被创建出来了也马上会消失：

1. MSG msg = { 0 };
   
2. while (GetMessage(&msg, NULL, 0, 0))
   
3. {
   
4.         TranslateMessage(&msg);
   
5.         DispatchMessage(&msg);
   
6. }

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cqzj70

CreateWindowEx
The CreateWindowEx function creates an overlapped, pop-up, or child window with an extended window style; otherwise, this function is identical to the CreateWindow function. For more information about creating a window and for full descriptions of the other parameters of CreateWindowEx, see CreateWindow.

HWND CreateWindowEx(
  DWORD dwExStyle,      // extended window style
  LPCTSTR lpClassName,  // registered class name
  LPCTSTR lpWindowName, // window name
  DWORD dwStyle,        // window style
  int x,                // horizontal position of window
  int y,                // vertical position of window
  int nWidth,           // window width
  int nHeight,          // window height
  HWND hWndParent,      // handle to parent or owner window
  HMENU hMenu,          // menu handle or child identifier
  HINSTANCE hInstance,  // handle to application instance
  LPVOID lpParam        // window-creation data
);

Debug

改完后的代码如下：

1. #include <windows.h>
   
2. 
   
3. LRESULT CALLBACK windowproc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
   
4. {
   
5.         return DefWindowProc(hwnd, uMsg, wParam, lParam);
   
6. }
   
7. 
   
8. int WINAPI WinMain(HINSTANCE hinstance, HINSTANCE Hinstance, LPSTR lpCmdLine, int cmdshow)
   
9. {
   
10.         const WCHAR *class_name = L"simple class name";
    
11.         WNDCLASS wndclass = { NULL };
    
12.         wndclass.lpfnWndProc = windowproc;
    
13.         wndclass.hInstance = hinstance;
    
14.         wndclass.lpszClassName = class_name;
    
15.         RegisterClass(&wndclass);
    
16. 
    
17.         HWND windowhwnd = CreateWindowEx(1, class_name, L"first windows window", WS_TILEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hinstance, NULL);
    
18. 
    
19.         ShowWindow(windowhwnd, cmdshow);
    
20. 
    
21.         // 主消息循环:
    
22.         MSG msg = { 0 };
    
23.         while (GetMessage(&msg, NULL, 0, 0))
    
24.         {
    
25.                 TranslateMessage(&msg);
    
26.                 DispatchMessage(&msg);
    
27.         }
    
28. 
    
29.         return 0;
    
30. }
    

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ww1724

Debug 发表于 2019-2-26 22:06
楼主这个代码范了几个致命的错误啊：
1、HWND windowhwnd = CreateWindowEx(...); 之后，并没有加 if 判断 ...

谢谢了大佬,按照你说的果然搞定了