检测到U盘插入

只要你程序运行着，一旦有U盘插入，操作系统（我指的是Windows OS）会向每个进程广播WM_DEVICECHANGE消息的，只要响应该消息就可以了

// 优盘插入

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://U盘插入
          DriveInfo[] s = DriveInfo.GetDrives();
          foreach (DriveInfo drive in s)
          {
            if (drive.DriveType == DriveType.Removable)
            {
              Upath = drive.Name.ToString();
              string folderpath = Upath + @"\taxbase";
              if (!Directory.Exists(folderpath))
              {
                Directory.CreateDirectory(folderpath);
              }
              string path = Upath + @"\taxbase\" + LoginUserInfo.LoginUser.Com_code + @".db";
              if (File.Exists(path))
              {
                MessageBox.Show("检测到U盘插入，可以更新数据！
              }              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: //U盘卸载          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);}