C实现USB插拔检测

　　-Begin-  前言
　　最近有学员咨询，如何实现串口设备的插拔检测。
　　传统的方式是不断地通过SerialPort.GetPortNames方法获取所有串口，判断是否有变化。
　　但是更合适的方式，应该是通过Windows消息来实现。 代码  #region 检测USB插拔          public const int WM_DEVICECHANGE = 0x219;         public const int DBT_DEVICEARRIVAL = 0x8000;         public const int DBT_CONFIGCHANGECANCELED = 0x0019;         public const int DBT_CONFIGCHANGED = 0x0018;         public const int DBT_CUSTOMEVENT = 0x8006;         public const int DBT_DEVICEQUERYREMOVE = 0x8001;         public const int DBT_DEVICEQUERYREMOVEFAILED = 0x8002;         public const int DBT_DEVICEREMOVECOMPLETE = 0x8004;         public const int DBT_DEVICEREMOVEPENDING = 0x8003;         public const int DBT_DEVICETYPESPECIFIC = 0x8005;         public const int DBT_DEVNODES_CHANGED = 0x0007;         public const int DBT_QUERYCHANGECONFIG = 0x0017;         public const int DBT_USERDEFINED = 0xFFFF;          protected override void WndProc(ref Message m)         {              try             {                 if (m.Msg == WM_DEVICECHANGE)                 {                     switch (m.WParam.ToInt32())                     {                         case WM_DEVICECHANGE:                             break;                         case DBT_DEVICEARRIVAL:                             MessageBox.Show(＂判断检测USB插入电脑＂);                              DriveInfo[] s = DriveInfo.GetDrives();                             foreach (DriveInfo drive in s)                             {                                 if (drive.DriveType == DriveType.Removable)                                 {                                     break;                                 }                             }                             break;                         case DBT_CONFIGCHANGECANCELED:                             break;                         case DBT_CONFIGCHANGED:                             break;                         case DBT_CUSTOMEVENT:                             break;                         case DBT_DEVICEQUERYREMOVE:                             break;                         case DBT_DEVICEQUERYREMOVEFAILED:                             break;                         case DBT_DEVICEREMOVECOMPLETE:                             MessageBox.Show(＂＂判断检测USB拔出电脑＂);                             break;                         case DBT_DEVICEREMOVEPENDING:                             break;                         case DBT_DEVICETYPESPECIFIC:                             break;                         case DBT_DEVNODES_CHANGED:                             break;                         case DBT_QUERYCHANGECONFIG:                             break;                         case DBT_USERDEFINED:                             break;                         default:                             break;                     }                 }             }             catch (Exception ex)             {                 MessageBox.Show(ex.Message);             }             base.WndProc(ref m);         }         #endregion
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