驱动器挂载或更改状态时检测到（WPF的WM_DEVICECHANGE）？

Question

我正在为WPF编写一个目录选择器控件，并且我希望在目录树被挂载或卸载时，或者准备就绪或未准备好时（例如，用户插入或删除CD），从驱动器中添加/ 。我正在寻找类似于WM_DEVICECHANGE的系统事件。

康斯坦丁

Answer 1

我使用WMI来实现这样的事情（像理查德在他的回答说明）

using System.Management; 
using System; 

... 

private void SubscribeToCDInsertion() 
{ 
    WqlEventQuery q; 
    ManagementOperationObserver observer = new ManagementOperationObserver(); 

    // Bind to local machine 
    ConnectionOptions opt = new ConnectionOptions(); 
    opt.EnablePrivileges = true; //sets required privilege 
    ManagementScope scope = new ManagementScope("root\\CIMV2", opt); 

    q = new WqlEventQuery(); 
    q.EventClassName = "__InstanceModificationEvent"; 
    q.WithinInterval = new TimeSpan(0, 0, 1); 
    // DriveType - 5: CDROM 
    q.Condition = @"TargetInstance ISA 'Win32_LogicalDisk' and TargetInstance.DriveType = 5"; 
    var w = new ManagementEventWatcher(scope, q); 
    try 
    { 

     // register async. event handler 
     w.EventArrived += new EventArrivedEventHandler(driveInsertEvent); 
     w.Start(); 

    } 
    catch (Exception e) 
    { 
     w.Stop(); 
    } 

} 

void driveInsertEvent(object sender, EventArrivedEventArgs e) 
{ 
    // Get the Event object and display it 
    PropertyData pd = e.NewEvent.Properties["TargetInstance"]; 

    if (pd != null) 
    { 
     ManagementBaseObject mbo = pd.Value as ManagementBaseObject; 
     // if CD removed VolumeName == null 
     if (mbo.Properties["VolumeName"].Value != null) 
     { 
      //do something 
     } 
    } 
} 

编辑：不是我发明的代码我自己，我想我从here

Answer 2

您可以：

• 使用WMI和WMI事件，以检测硬件改动。
• 使用隐藏的WinForms窗口，并覆盖WinProc方法来获取WM_DEVICECHANGE。

Answer 3

即使您使用的是WPF，仍然可以拦截WM_DEVICECHANGE。您可以使用WPF回调方法附加到现有的窗口过程，或者您可以使用System.Windows.Forms.NativeWindow（我的首选方法，更多控制和更简单，但您确实需要添加对System.Windows.Forms.dll的引用）

// in your window's code behind 
private static int WM_DEVICECHANGE = 0x0219; 

protected override void OnSourceInitialized(EventArgs e) 
{ 
    WindowInteropHelper helper = new WindowInteropHelper(this); 
    SystemEventIntercept intercept = new SystemEventIntercept(helper.Handle); 
    base.OnSourceInitialized(e); 
} 

class SystemEventIntercept : System.Windows.Forms.NativeWindow 
{ 
    public SystemEventIntercept(IntPtr handle) 
    { 
     this.AssignHandle(handle); 
    } 

    protected override void WndProc(ref Winforms.Message m) 
    { 
     if (m.Msg == WM_DEVICECHANGE) 
     { 
      // do something 
     } 

     base.WndProc(ref m); 
    } 
} 

Answer 4

的得到它下面的代码为我工作。它订阅了DriveType = 2和DriveType = 5事件来检测cd-rom和usb。因为我不需要知道驱动器是已安装还是未安装，或者cd已被移除或插入，所以代码不检查该问题。对于USB挂载，e.NewEvent.ClassPath可用于判断驱动器是连接还是断开连接。

另外，我在网上发现了一些令人困惑的言论，说单独订阅DriveType = 5的事件也会检测到USB挂载。这对我不起作用。

康斯坦丁

using System; 
using System.Management; 

namespace consapp 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      const string QUERY = @"select * from __InstanceOperationEvent within 1 where TargetInstance isa 'Win32_LogicalDisk' and (TargetInstance.DriveType=2 or TargetInstance.DriveType=5)"; 

      Program p = new Program(); 

      ManagementEventWatcher w = new ManagementEventWatcher(new WqlEventQuery(QUERY)); 

      w.EventArrived += new EventArrivedEventHandler(p.OnWMIEvent); 
      w.Start(); 

      Console.ReadKey(); 

      w.Stop(); 
     } 

     public void OnWMIEvent(object sender, EventArrivedEventArgs e) 
     { 
      PropertyData p = e.NewEvent.Properties["TargetInstance"]; 

      if (p != null) 
      { 
       ManagementBaseObject mbo = p.Value as ManagementBaseObject; 

       PropertyData deviceid = mbo.Properties["DeviceID"]; 
       PropertyData drivetype = mbo.Properties["DriveType"]; 

       Console.WriteLine("{0}-{1}:{2}", deviceid.Value, drivetype.Value, e.NewEvent.ClassPath); 
      } 
     } 
    } 
}