MFC视频教学第一课，做一个简单的界面，理解应用程序和操作系统之间的消息传递机制

#include <windows.h>
#include <stdio.h>
 
LRESULT CALLBACK WinSunProc(
       HWND hwnd,
       UINT uMsg,
       WPARAM wParam,
       LPARAM lParam
);
 
//WinMain是操作系统调用的，是系统的入口函数
int WINAPI WinMain(
       HINSTANCE hInstance,//当前应运程序的实例号
       HINSTANCE hPrevInstance,
       LPSTR lpCmdLine,//字符串类型的指针，命令行参数
       int nCmdShow//程序窗口显示的状态
)
{
       //创建一个窗口类
       WNDCLASS wndclass;
       wndclass.cbClsExtra=0;//为类分配的额外内存，一般置0
       wndclass.cbWndExtra=0;//为窗口分配的额外内存，一般置0
       wndclass.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);//窗口的背景
       wndclass.hCursor=LoadCursor(NULL,IDC_CROSS);//鼠标的类型
       wndclass.hIcon=LoadIcon(NULL,IDI_ERROR);//图标的类型
       wndclass.hInstance=hInstance;//当前应运程序的实例号
       wndclass.lpfnWndProc=WinSunProc;//指向窗口过程函数的指针
       wndclass.lpszClassName="Winxin2010";//类的名字
       wndclass.lpszMenuName=NULL;//菜单的名字
       wndclass.style=CS_HREDRAW | CS_VREDRAW;//窗口特性的组合
 
       //注册一个类
       RegisterClass(&wndclass);
 
       //创建一个窗口
       HWND hwnd;
       hwnd=CreateWindow("Winxin2010","索广宇自学MFC",WS_OVERLAPPEDWINDOW,
              100,100,600,400,NULL,NULL,hInstance,NULL);
 
       //显示及更新窗口
       ShowWindow(hwnd,SW_SHOWNORMAL);
       UpdateWindow(hwnd);
 
       //消息循环
       MSG msg;
       while(GetMessage(&msg,NULL,0,0))//GetMessage()的作用是从消息队列中取出消息
       {
              TranslateMessage(&msg);
              DispatchMessage(&msg);
       }
       return 0;
}
LRESULT CALLBACK WinSunProc(
       HWND hwnd,
       UINT uMsg,
       WPARAM wParam,
       LPARAM lParam
)
{
       switch(uMsg)
       {
       case WM_CHAR:
              char szChar[20];
              sprintf(szChar,"char is %d",wParam);
              MessageBox(hwnd,szChar,"索广宇加油",MB_OK);
              break;
       case WM_LBUTTONDOWN:
              MessageBox(hwnd,"Mouse Click!","索广宇加油",MB_OK);
              HDC hdc;
              hdc=GetDC(hwnd);
              TextOut(hdc,0,50,"索广宇爱邢飘！",strlen("索广宇爱邢飘！"));
              ReleaseDC(hwnd,hdc);
              break;
       case WM_PAINT:
              HDC hDC;
              PAINTSTRUCT ps;
              hDC=BeginPaint(hwnd,&ps);
              TextOut(hDC,0,0,"执子之手，与子协老！",strlen("执子之手，与子协老！"));
              EndPaint(hwnd,&ps);
              break;
       case WM_CLOSE:
              if(IDYES==MessageBox(hwnd,"真的要退出吗？","索广宇加油",MB_YESNO))
              {
                     DestroyWindow(hwnd);
              }
              break;
       case WM_DESTROY:
              PostQuitMessage(0);
              break;
       default:
              return DefWindowProc(hwnd,uMsg,wParam,lParam);
       }
       return 0;
}