CreateWindow的出错解决

CreateWindow返回NULL，而且GetLastError()也返回0，代码如下：

WNDCLASSEX wc =
 {
  sizeof( WNDCLASSEX ), CS_CLASSDC, NULL/*gWndProc 注意这里直接把它写成 NULL ,贪方便啊.*/, 
  0L, 0L,
  GetModuleHandle( NULL ), NULL, NULL, NULL, NULL,
  classname, NULL
 };
 RegisterClassEx( &wc );

HWND hWnd = CreateWindow( classname, wndname,
  WS_DLGFRAME | WS_SYSMENU, 0, 0,m_ScreenWidth, m_ScreenHeight,
  ::GetDesktopWindow(), NULL,wc.hInstance, NULL );

 

把窗口回调函数写成了 NULL ，发现窗口没有显示出来。。,CreateWindow 函数调用 失败...

笨蛋,窗口回调函数都没有.那么消息流向呢.. 这样当然不行的啊..

 

 #include <windows.h>
 #include <stdio.h>

 LRESULT CALLBACK WinSunProc(
   HWND hwnd,      // handle to window
   UINT uMsg,      // message identifier
   WPARAM wParam,  // first message parameter
   LPARAM lParam   // second message parameter
 );

 int WINAPI WinMain(
   HINSTANCE hInstance,      // handle to current instance
   HINSTANCE hPrevInstance,  // handle to previous instance
   LPSTR lpCmdLine,          // command line
   int nCmdShow              // show state
 )
 {
     WNDCLASS wndcls;
     wndcls.cbClsExtra=;
     wndcls.cbWndExtra=;
     wndcls.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);
     wndcls.hCursor=LoadCursor(NULL,IDC_CROSS);
     wndcls.hIcon=LoadIcon(NULL,IDI_ERROR);
     wndcls.hInstance=hInstance;
     wndcls.lpfnWndProc=WinSunProc;
     wndcls.lpszClassName="sunxin2006";
     wndcls.lpszMenuName=NULL;
     wndcls.style=CS_HREDRAW | CS_VREDRAW;
     RegisterClass(&wndcls);

     HWND hwnd;
     hwnd=CreateWindow("sunxin2006","http://www.sunxin.org",WS_OVERLAPPEDWINDOW,
         ,,,,NULL,NULL,hInstance,NULL);

     ShowWindow(hwnd,SW_SHOWNORMAL);
     UpdateWindow(hwnd);

     MSG msg;
     while(GetMessage(&msg,NULL,,))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }
     return msg.wParam;
 }

 LRESULT CALLBACK WinSunProc(
   HWND hwnd,      // handle to window
   UINT uMsg,      // message identifier
   WPARAM wParam,  // first message parameter
   LPARAM lParam   // second message parameter
 )
 {
     switch(uMsg)
     {
     case WM_CHAR:
         char szChar[];
         sprintf(szChar,"char code is %d",wParam);
         MessageBox(hwnd,szChar,"char",);
         break;
     case WM_LBUTTONDOWN:
         MessageBox(hwnd,"mouse clicked","message",);
         HDC hdc;
         hdc=GetDC(hwnd);
         TextOut(hdc,,,"程序员之家",strlen("程序员之家"));
         //ReleaseDC(hwnd,hdc);
         break;
     case WM_PAINT:
         HDC hDC;
         PAINTSTRUCT ps;
         hDC=BeginPaint(hwnd,&ps);
         TextOut(hDC,,,"http://www.sunxin.org",strlen("http://www.sunxin.org"));
         EndPaint(hwnd,&ps);
         break;
     case WM_CLOSE:
         if(IDYES==MessageBox(hwnd,"是否真的结束？","message",MB_YESNO))
         {
             DestroyWindow(hwnd);
         }
         break;
     case WM_DESTROY:
         PostQuitMessage();
         break;
     default:
         return DefWindowProc(hwnd,uMsg,wParam,lParam);
     }
     return ;
 }