#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
)
{
//设计一个窗口类
   WNDCLASS wndcls;
   wndcls.cbClsExtra=0;
   wndcls.cbWndExtra=0;
   wndcls.hCursor=LoadCursor(NULL,IDC_CROSS);
   wndcls.hIcon=LoadIcon(NULL,IDI_ERROR);
   wndcls.hInstance=hInstance;  //应用程实例句柄由WinMain函数传进来
   wndcls.lpfnWndProc=WinSunProc;
   wndcls.lpszClassName="sunxin2006";
   wndcls.lpszMenuName=NULL;
   wndcls.style=CS_HREDRAW|CS_VREDRAW;
   RegisterClass(&wndcls);
 
  //创建窗口，定义一个变量用来保存成功创建窗口后返回的句柄
  HWND hwnd;
  hwnd=CreateWindow("sunxing2006","http://www.sunxing.org",
       WS_OVERLAPPEDWINDOW,0,0,600,400,NULL,NULL,hInstance,NULL
                  );
    //显示及刷新窗口
  ShowWindow(hwnd,SW_SHOWNORMAL);
  UpdateWindow(hwnd);
    //定义消息结构体，开始消息循环
   MSG  msg;
   while(GetMessage(&msg,NULL,0,0))
   {TranslateMessage(&msg);
    DispatchMessage(&msg);
   }
   return msg.wParam;
}
//编写窗口过程函数
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[20];
        sprintf(szChar,"char code is%d",wParam);
        MessageBox(hwnd,szChar,"char",0);
        break;
    case WM_LBUTTONDOWN:
        MessageBox(hwnd,"mouse clicked","message",0);
        HDC hdc;
        hdc=GetDC(hwnd);    //不能在响应WM_PAINT消息时调用
        TextOut(hdc,0,50,"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);   //BeginPaint只能在响应WM_PAINT消息时调用
        TextOut(hDC,0,0,"http://www.sunxing.org",strlen("http://www.sunxing.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(0);
        break;
    default:
        return DefWindowProc(hwnd,uMsg,wParam,lParam);
    }
    return 0;
}
编译时没有问题，能运行，进程中有这个程序在运行，但是就是不能显示窗口，为什么啊？谢谢了