Windows关机检测

//这个.h中没有, 定义
#define ENDSESSION_CLOSEAPP 0x1
#define ENDSESSION_CRITICAL 0x40000000

LRESULT CTestSystemPowerOffDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
    // TODO: Add your specialized code here and/or call the base class
    if(WM_ENDSESSION == message)
    {
        AfxMessageBox("WM_ENDSESSION");

        BOOL bEnd = (BOOL)wParam;
        if((bEnd) && (ENDSESSION_CLOSEAPP == lParam))
        {
            AfxMessageBox("the session is being ended");
        }
        else if((bEnd) && (ENDSESSION_CRITICAL == lParam))
        {
            AfxMessageBox("The application is forced to shut down");
        }
        else if((bEnd) && (ENDSESSION_LOGOFF == lParam))
        {
            AfxMessageBox("The user is logging off.");
        }
        /************************************************************************/
        /* WM_ENDSESSION
        /* 只要符合(WM_ENDSESSION && bEnd), 我们就可以认为计算机关机了或注销了
        /* 这个时候，不能做的就别做了(例如: 去访问驱动程序, 或调用第三方的API)，
        /* 该保存的就保存.
        */
        /************************************************************************/
    }
   
    return CDialog::WindowProc(message, wParam, lParam);
}

 

资料来源：http://msdn.microsoft.com/en-us/library/aa376889%28VS.85%29.aspx

WM_ENDSESSION Message

The WM_ENDSESSION message is sent to an application after the system processes the results of the WM_QUERYENDSESSION message. The WM_ENDSESSION message informs the application whether the session is ending.

A window receives this message through its WindowProc function.

Copy

LRESULT CALLBACK WindowProc( 

  HWND hwnd,      // handle to window 

  UINT uMsg,      // message identifier 

  WPARAM wParam,  // end-session option 

  LPARAM lParam   // logoff option

);

Parameters

hwnd

A handle to the window.

uMsg

The WM_ENDSESSION identifier.

wParam

If the session is being ended, this parameter is TRUE; the session can end any time after all applications have returned from processing this message. Otherwise, it is FALSE.

lParam

This parameter can be one or more of the following values. If this parameter is 0, the system is shutting down or restarting (it is not possible to determine which event is occurring).

ValueMeaning

ENDSESSION_CLOSEAPP

0x1

If wParam is TRUE, the application must shut down. Any data should be saved automatically without prompting the user (for more information, see Remarks). The Restart Manager sends this message when the application is using a file that needs to be replaced, when it must service the system, or when system resources are exhausted. The application will be restarted if it has registered for restart using the RegisterApplicationRestart function. For more information, see Guidelines for Applications.

If wParam is FALSE, the application should not shut down.

ENDSESSION_CRITICAL

0x40000000

The application is forced to shut down.

ENDSESSION_LOGOFF

0x80000000

The user is logging off. For more information, see Logging Off.

 

Note that this parameter is a bit mask. To test for this value, use a bit-wise operation; do not test for equality.

Return Value

If an application processes this message, it should return zero.

Remarks

Applications that have unsaved data could save the data to a temporary location and restore it the next time the application starts. It is recommended that applications save their data and state frequently; for example, automatically save data between save operations initiated by the user to reduce the amount of data to be saved at shutdown.

The application need not call the DestroyWindow or PostQuitMessage function when the session is ending.