Jak sprawdzić, czy dane urządzenie USB jest podłączone?

Question

Nasza aplikacja WinForm obsługuje niestandardowy kontroler używający SDK producenta, ale nie ma możliwości sprawdzenia, czy urządzenie jest obecne, czy nie. Jak sprawdzić, czy dane urządzenie USB jest podłączone?

Answer 1

Do monitorowania urządzeń służy następująca klasa, której można użyć do wykrycia urządzenia USB.

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 
    } 
} 

Edit

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