如何检查给定的USB设备是否插入？

Question

我们的winforms应用程序支持使用制造商SDK的自定义控制器，但不支持检测设备是否存在。如何检查给定的USB设备是否插入？

Answer 1

以下类用于监视设备，您可以使用它来检测USB设备。

using System; 
using System.Collections.Generic; 
using System.Text; 
using System.Management; 

namespace DeviceMonitor.Event 
{ 
    /// <summary>Media watcher delegate.</summary> 
    /// <param name="sender"></param> 
    /// <param name="driveStatus"></param> 
    public delegate void MediaWatcherEventHandler(object sender, DeviceMonitor.Event.MediaEvent.DriveStatus driveStatus); 

    /// <summary>Class to monitor devices.</summary> 
    public class MediaEvent 
    { 
     #region Variables 

     /*------------------------------------------------------------------------*/ 
     private string m_logicalDrive; 
     private ManagementEventWatcher m_managementEventWatcher = null; 
     /*------------------------------------------------------------------------*/ 
     #endregion 

     #region Events 
     /*------------------------------------------------------------------------*/ 
     public event MediaWatcherEventHandler MediaWatcher; 
     /*------------------------------------------------------------------------*/ 
     #endregion 


     #region Enums 
     /*------------------------------------------------------------------------*/ 
     /// <summary>The drive types.</summary> 
     public enum DriveType 
     { 
      Unknown = 0, 
      NoRootDirectory = 1, 
      RemoveableDisk = 2, 
      LocalDisk  = 3, 
      NetworkDrive = 4, 
      CompactDisk  = 5, 
      RamDisk   = 6 
     } 

     /// <summary>The drive status.</summary> 
     public enum DriveStatus 
     { 
      Unknown = -1, 
      Ejected = 0, 
      Inserted = 1, 
     } 

     /*-----------------------------------------------------------------------*/ 
     #endregion 


     #region Monitoring 
     /*-----------------------------------------------------------------------*/ 
     /// <summary>Starts the monitoring of device.</summary> 
     /// <param name="path"></param> 
     /// <param name="mediaEvent"></param> 
     public void Monitor(string path, MediaEvent mediaEvent) 
     { 
      if(null == mediaEvent) 
      { 
       throw new ArgumentException("Media event cannot be null!"); 
      } 

      //In case same class was called make sure only one instance is running 
      ///////////////////////////////////////////////////////////// 
      this.Exit(); 

      //Keep logica drive to check 
      ///////////////////////////////////////////////////////////// 
      this.m_logicalDrive = this.GetLogicalDrive(path); 

      WqlEventQuery wql; 
      ManagementOperationObserver observer = new ManagementOperationObserver(); 

      //Bind to local machine 
      ///////////////////////////////////////////////////////////// 
      ConnectionOptions opt = new ConnectionOptions(); 

      //Sets required privilege 
      ///////////////////////////////////////////////////////////// 
      opt.EnablePrivileges = true; 
      ManagementScope scope = new ManagementScope("root\\CIMV2", opt); 

      try 
      { 
       wql = new WqlEventQuery(); 
       wql.EventClassName = "__InstanceModificationEvent"; 
       wql.WithinInterval = new TimeSpan(0, 0, 1); 

       wql.Condition = String.Format(@"TargetInstance ISA 'Win32_LogicalDisk' and TargetInstance.DeviceId = '{0}'", this.m_logicalDrive); 
       this.m_managementEventWatcher = new ManagementEventWatcher(scope, wql); 

       //Register async. event handler 
       ///////////////////////////////////////////////////////////// 
       this.m_managementEventWatcher.EventArrived += new EventArrivedEventHandler(mediaEvent.MediaEventArrived); 
       this.m_managementEventWatcher.Start(); 
      } 
      catch(Exception e) 
      { 
       this.Exit(); 
       throw new Exception("Media Check: " + e.Message); 
      } 
     } 

     /// <summary>Stops the monitoring of device.</summary> 
     public void Exit() 
     { 
      //In case same class was called make sure only one instance is running 
      ///////////////////////////////////////////////////////////// 
      if(null != this.m_managementEventWatcher) 
      { 
        try 
        { 
         this.m_managementEventWatcher.Stop(); 
         this.m_managementEventWatcher = null; 
        } 
        catch {} 
      } 
     } 
     /*-----------------------------------------------------------------------*/ 
     #endregion 


     #region Helpers 
     /*-----------------------------------------------------------------------*/ 

     private DriveStatus m_driveStatus = DriveStatus.Unknown; 

     /// <summary>Triggers the event when change on device occured.</summary> 
     /// <param name="sender"></param> 
     /// <param name="e"></param> 
     private void MediaEventArrived(object sender, EventArrivedEventArgs e) 
     { 

      // Get the Event object and display it 
      PropertyData pd = e.NewEvent.Properties["TargetInstance"]; 
      DriveStatus driveStatus = this.m_driveStatus; 

      if(pd != null) 
      { 
       ManagementBaseObject mbo = pd.Value as ManagementBaseObject; 
       System.IO.DriveInfo info = new System.IO.DriveInfo((string)mbo.Properties["DeviceID"].Value); 
       driveStatus = info.IsReady ? DriveStatus.Inserted : DriveStatus.Ejected; 
      } 

      if(driveStatus != this.m_driveStatus) 
      { 
       this.m_driveStatus = driveStatus; 
       if(null != MediaWatcher) 
       { 
        MediaWatcher(sender, driveStatus); 
       } 
      } 
     } 


     /// <summary>Gets the logical drive of a given path.</summary> 
     /// <param name="path"></param> 
     /// <returns></returns> 
     private string GetLogicalDrive(string path) 
     { 
      System.IO.DirectoryInfo dirInfo = new System.IO.DirectoryInfo(path); 
      string root = dirInfo.Root.FullName; 
      string logicalDrive = root.Remove(root.IndexOf(System.IO.Path.DirectorySeparatorChar)); 
      return logicalDrive; 
     } 
     /*-----------------------------------------------------------------------*/ 
     #endregion 
    } 
} 

编辑

从http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/09912cee-4d2d-4efd-82a0-da20024b868b