[MFC]U盘检测

前言

　　本文主要是讲在MFC中使用消息队列，并在消息中捕获系统USB插入、卸载U盘的事件。

 

正文

　　一、MFC中使用消息队列

　　　　1.1　　声明

virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam);

　　　　1.2　　实现

LRESULT CTestDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
     return  CDialog::WindowProc(message,wParam,lParam);
}

　　　　　　本示例是继承CDialog。

 

　　二、捕获U盘插入、卸载事件

LRESULT CTestDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam) 
{
     switch  (message)
    {
         // WM_DEVICECHANGE，系统硬件改变发出的系统消息
         case  WM_DEVICECHANGE:
        {
            PDEV_BROADCAST_HDR lpdb = (PDEV_BROADCAST_HDR)lParam;
             switch (wParam)
            {
                 case  WM_DEVICECHANGE:
                     break ;
                 case  DBT_DEVICEARRIVAL: // DBT_DEVICEARRIVAL，设备检测结束，并且可以使用
                {
                     if (lpdb -> dbch_devicetype  ==  DBT_DEVTYP_VOLUME) // 逻辑卷
                    {
                        PDEV_BROADCAST_VOLUME lpdbv  =   (PDEV_BROADCAST_VOLUME)lpdb;
                         switch (lpdbv -> dbcv_flags)
                        {
                             case   0 :                 // U盘
                            {
                                CString decDriver;
                                decDriver  =  FirstDriveFromMask(lpdbv  -> dbcv_unitmask);
                                TRACE1( " 检测到U盘:[%s]插入!\n " ,decDriver.GetBuffer( 0 ));
                            }
                                 break ;
                             case  DBTF_MEDIA:     // 光盘
                                TRACE1( " 检测到光盘:[%c]插入!\n " ,FirstDriveFromMask(lpdbv  -> dbcv_unitmask));
                                 break ;
                        }
                    }
                }
                     break ;
                 case  DBT_DEVICEREMOVECOMPLETE: // DBT_DEVICEREMOVECOMPLETE,设备卸载或者拔出
                {
                     if (lpdb -> dbch_devicetype  ==  DBT_DEVTYP_VOLUME) // 逻辑卷
                    {
                        PDEV_BROADCAST_VOLUME lpdbv  =   (PDEV_BROADCAST_VOLUME)lpdb;
                         switch (lpdbv -> dbcv_flags)
                        {
                             case   0 :                 // U盘
                            {
                                CString decDriver;
                                decDriver  =  FirstDriveFromMask(lpdbv  -> dbcv_unitmask);
                                TRACE1( " 检测到U盘:[%s]拔出!\n " ,decDriver.GetBuffer( 0 ));
                            }
                                 break ;
                             case  DBTF_MEDIA:     // 光盘
                                
                                 break ;
                        }
                    }
                }
                     break ;
            }
        }
         break ;
    }
     return  CDialog::WindowProc(message,wParam,lParam);  
}

　　三、效果图

　　 

 

　　四、文章修改

　　　　4.1　　2010-5-7　　MFC中使用不要使用SetWindowLong方式来获取消息队列，否则会出现无法关闭窗口的问题。

　　　　4.2　　 2013-2-17　　感谢网友提醒，CString getBuffer后应调用ReleaseBuffer

 

 

结束语

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