驅動器掛載或更改狀態時檢測到（WPF的WM_DEVICECHANGE）？

Question

我正在爲WPF編寫一個目錄選擇器控件，並且我希望在目錄樹被掛載或卸載時，或者準備就緒或未準備好時（例如，用戶插入或刪除CD），從驅動器中添加/ 。我正在尋找類似於WM_DEVICECHANGE的系統事件。

康斯坦丁

Answer 1

我使用WMI來實現這樣的事情（像理查德在他的回答說明）

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 
     } 
    } 
} 

編輯：不是我發明的代碼我自己，我想我從here

Answer 2

您可以：

• 使用WMI和WMI事件，以檢測硬件改動。
• 使用隱藏的WinForms窗口，並覆蓋WinProc方法來獲取WM_DEVICECHANGE。

Answer 3

即使您使用的是WPF，仍然可以攔截WM_DEVICECHANGE。您可以使用WPF回調方法附加到現有的窗口過程，或者您可以使用System.Windows.Forms.NativeWindow（我的首選方法，更多控制和更簡單，但您確實需要添加對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

的得到它下面的代碼爲我工作。它訂閱了DriveType = 2和DriveType = 5事件來檢測cd-rom和usb。因爲我不需要知道驅動器是已安裝還是未安裝，或者cd已被移除或插入，所以代碼不檢查該問題。對於USB掛載，e.NewEvent.ClassPath可用於判斷驅動器是連接還是斷開連接。

另外，我在網上發現了一些令人困惑的言論，說單獨訂閱DriveType = 5的事件也會檢測到USB掛載。這對我不起作用。

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); 
      } 
     } 
    } 
}