c++ - 驱动器号重复

Question

我从 WM_DEVICECHANGE 收到设备插入和移除通知

我从 DBT_DEVTYP_DEVICEINTERFACE 获取 dbcc_name

我从DBT_DEVTYP_VOLUME中得到对应的盘符

如果我将设备一个接一个地插入，它会正常工作

但是如果我一次插入两个设备，我会得到重复的驱动器号

我该如何解决

请给我一些想法

我的代码片段

if ( DBT_DEVICEARRIVAL == wParam || DBT_DEVICEREMOVECOMPLETE == wParam )
{
     PDEV_BROADCAST_HDR pHdr = ( PDEV_BROADCAST_HDR )lParam;

     PDEV_BROADCAST_DEVICEINTERFACE pDevInf;

     PDEV_BROADCAST_VOLUME pDevVolume = reinterpret_cast<PDEV_BROADCAST_VOLUME>(lParam);

     switch( pHdr->dbch_devicetype )

     {
           case DBT_DEVTYP_DEVICEINTERFACE:
                pDevInf = ( PDEV_BROADCAST_DEVICEINTERFACE )pHdr;
      updateDevice( pDevInf, wParam , pDevVolume );
                break;

            case DBT_DEVTYP_VOLUME:
                  pDevVolume = ( PDEV_BROADCAST_VOLUME )pHdr;
                  QString aDrive = FirstDriveFromMask( pDevVolume->dbcv_unitmask );
                  break;

      }

}

Answer 1

DEV_BROADCAST_VOLUME文档提到了这条信息:

Although the dbcv_unitmask member may specify more than one volume in any message, this does not guarantee that only one message is generated for a specified event. Multiple system components may independently generate messages for logical volumes at the same time.

换句话说 - 一条消息可以携带有关(几乎)同时添加的多个卷的信息，但这并不能保证只会为这些卷生成一条消息。您应该为多个卷检查 dbcv_unitmask。