窗口进程问题

Question

为什么窗口销毁了,进程还在#include<windows.h>LRESULT CALLBACK MainWndProc(HWND,UINT,WPARAM,LPARAM);int WINAPI WinMain(
  HINSTANCE hInstance,     
  HINSTANCE hPrevInstance,  
  LPSTR lpCmdLine,          
  int nCmdShow  
  )
{
WNDCLASSEX wndclass;
wndclass.cbClsExtra=0;
wndclass.cbSize=sizeof(wndclass);
wndclass.cbWndExtra=0;
wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.hCursor=LoadCursor(NULL,IDC_APPSTARTING);
wndclass.hIcon=LoadIcon(NULL,IDI_ERROR);
wndclass.hIconSm=NULL;
wndclass.hInstance=hInstance;
wndclass.lpfnWndProc=MainWndProc;
wndclass.lpszClassName="zhao";
wndclass.lpszMenuName=NULL;
wndclass.style=CS_HREDRAW|CS_VREDRAW; RegisterClassEx(&wndclass); HWND hwnd=::CreateWindowEx(0,"zhao","love",WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL); if(!hwnd)
{
MessageBox(NULL,"Error","Error",MB_OK);
exit(-1);
} ::ShowWindow(hwnd,nCmdShow);
::UpdateWindow(hwnd); MSG msg; while(GetMessage(&msg,hwnd,NULL,NULL))
{
::TranslateMessage(&msg);
::DispatchMessage(&msg);
} return msg.wParam;}LRESULT CALLBACK MainWndProc(
        HWND hwnd,    
        UINT message,    
        WPARAM wParam,    
        LPARAM lParam)   
{
switch(message)
{
case WM_PAINT:
HDC hdc;
PAINTSTRUCT ps;
hdc=::BeginPaint(hwnd,&ps); ::EndPaint(hwnd,&ps);
break;
break;
case WM_CLOSE:
if(IDYES==MessageBox(hwnd,"是否退出?","退出",MB_YESNO))
{
DestroyWindow(hwnd);
}
break;
case WM_DESTROY:
::PostQuitMessage(0);
break;
default:
return ::DefWindowProc(hwnd,message,wParam,lParam);
}

return 0;
}

Answer 1

这是第一次写完全正常,真不知道这2个有撒区别
#include <windows.h>
#include<windows.h>LRESULT CALLBACK MainWndProc(HWND,UINT,WPARAM,LPARAM);int WINAPI WinMain(
  HINSTANCE hInstance,      // 现在实例句柄
  HINSTANCE hPrevInstance,  // 先前实例句柄
  LPSTR lpCmdLine,          // 参数
  int nCmdShow              // 显示状态
)
{
    WNDCLASSEX wc;
    wc.cbClsExtra=0;       //没有额外的类内存
    wc.cbWndExtra=0;      //没有额外的窗口内存
    wc.cbSize=sizeof(wc);    //结构的大小
    wc.hbrBackground=(HBRUSH)::GetStockObject(WHITE_BRUSH);   //背景
    wc.hCursor=LoadCursor(NULL,IDC_CROSS);   //光标
    wc.hIcon=LoadIcon(NULL,IDI_ASTERISK);    //图标
    wc.hIconSm=NULL;                //没有类的小图标
    wc.hInstance=hInstance;            //实例句柄名
    wc.lpfnWndProc=MainWndProc;        //函数窗口指针
    wc.lpszClassName="MainWndProc";        //窗口类的名称
    wc.lpszMenuName=NULL;        //菜单名称
    wc.style=CS_HREDRAW | CS_VREDRAW;        //窗口样式    RegisterClassEx(&wc);        //注册窗口类    //创建主窗口
    HWND hwnd=::CreateWindowEx(
        0,        //dwExStyle,扩展样式
        "MainWndProc",        //lpClassName,类名
        "My first Window",        //lpMenuName,标题
        WS_OVERLAPPEDWINDOW&~WS_MAXIMIZEBOX,    //dwStyle,窗口风格
        CW_USEDEFAULT,        //X,初始X的坐标
        CW_USEDEFAULT,        //Y,初始Y的坐标
        CW_USEDEFAULT,        //nWidth,宽度
        CW_USEDEFAULT,        //nHeight,高度
        NULL,            //hWndParent,父窗口句柄
        NULL,            //hMenu,菜单句柄
        hInstance,        //hInstance,程序实例句柄
        NULL);            //lpParam,用户数据    if(!hwnd)
    {
        ::MessageBox(NULL,"创建窗口出错","ERROR",MB_OK);
        exit(-1);
    }    //显示窗口,刷新窗口客户区
    ::ShowWindow(hwnd,nCmdShow);
    ::UpdateWindow(hwnd);    //从消息队列中取出消息,交给窗口函数处理,直到GetMessage返回FALSE,结束消息循环
    MSG msg;
    while(::GetMessage(&msg,NULL,0,0))
    {
        ::TranslateMessage(&msg);    //转化键盘消息
        ::DispatchMessage(&msg);    //将消息发送到相应的窗口函数
    }    return msg.wParam;        //当GetMessage返回FALSE时程序结束
}LRESULT CALLBACK MainWndProc(
        HWND hwnd,    //窗口句柄
        UINT message,    //消息
        WPARAM wParam,    //低位菜单ID号,高位消息通知码对子窗口控件有效
        LPARAM lParam)    //发送消息时,低位鼠标x坐标,高位Y坐标
{    switch(message)
    {
    case WM_PAINT:        //窗口客户区重绘
        HDC hdc;
        PAINTSTRUCT ps;
        //使无效的客户区有并行,并取得设备环境句柄
        hdc=::BeginPaint(hwnd,&ps);
   
        ::EndPaint(hwnd,&ps);
        break;
    case WM_CLOSE:        //关闭
        if(IDYES==MessageBox(hwnd,"是否退出?","退出",MB_YESNO))
        {
            DestroyWindow(hwnd);
        }
        break;
    case WM_DESTROY:
        //向消息列队投递一个WM_OUT消息,促使GetMessage函数返回为0,结束循环
        ::PostQuitMessage(0);
        break;
    default:
        //将不处理的消息交给系统做默认处理
        return ::DefWindowProc(hwnd,message,wParam,lParam);    }
    return 0;
}

Answer 2

 while(GetMessage(&msg,hwnd,NULL,NULL))
=========================
经典错误，应该是 while(GetMessage(&msg,NULL,NULL,NULL)),GetMessage的第二个参数为NULL，否则收不到WM_QUIT消息造成进程无法关闭