Monitor USB drives and retrieve device Info using a DeviceWatcher?

Question

I\'m a WinForms developer and I already knew how to monitor the USB\'s that connects or disconnects using WMI, but time ago I\'d discovered the DeviceWatche

Answer 1

This will watch for the Arrival and Removal of USB drives, and report the DriveLetter, Volume Label and device serial number. It raises 2 Events for your convenience:

Public Event DeviceAdded(sender As Object, e As USBWatcherEventArgs)
Public Event DeviceRemoved(sender As Object, e As USBWatcherEventArgs)

This only watches for a new drive added/removed, it will not detect things like a CD being ejected or inserted, or inserting media into a card reader slot.

Imports System.Management

Public Class USBWatcher

    ' alternate method to use one event with an extra
    ' event property to report the action
    'Public Enum WatcherActions
    '    DriveInserted = 1
    '    DriveRemoved = 2
    'End Enum

    ' USB device added/removed args
    Public Class USBWatcherEventArgs
        Inherits EventArgs

        'Public Property WatcherAction As WatcherActions
        Public Property DriveLetter As String
        Public Property VolumeName As String
        Public Property VolumeSerial As String

        Friend Sub New(drv As String, vol As String, ser As String)
            DriveLetter = drv
            VolumeName = vol
            VolumeSerial = ser
            'WatcherAction = act
        End Sub

    End Class

    Private WithEvents Watcher As ManagementEventWatcher

    Public Event DeviceAdded(sender As Object, e As USBWatcherEventArgs)
    Public Event DeviceRemoved(sender As Object, e As USBWatcherEventArgs)

    Private pnpCol As Dictionary(Of String, Management.ManagementObject)

    Public Sub New()

    End Sub

    Public Sub StartWatching()

        ' get USBs currently attached
        pnpCol = GetUSBDevices()

        Dim arriveQuery = New WqlEventQuery("Select * from Win32_DeviceChangeEvent")
        Watcher = New ManagementEventWatcher(arriveQuery)

        ' we are watching you
        Watcher.Start()

    End Sub

    Public Sub StopWatching()
        Watcher.Stop()

    End Sub

    Private Function GetUSBDevices() As Dictionary(Of String,
                        Management.ManagementObject)

        Dim col As New Dictionary(Of String, Management.ManagementObject)

        Dim moSearch As New Management.ManagementObjectSearcher("Select * from Win32_LogicalDisk")
        Dim moReturn As Management.ManagementObjectCollection = moSearch.Get


        For Each mo As Management.ManagementObject In moReturn
            'Console.WriteLine("====")
            'DebugProperties(mo)

            ' some USB external drives report as DriveType 3 (local disk), but are
            ' in fact removable.  So monitor all disk drives.
            If col.ContainsKey(mo("DeviceID").ToString) = False Then
                col.Add(mo("DeviceID").ToString, mo)
            End If

        Next

        Return col
    End Function

    Private inEvent As Boolean = False

    Private Sub arrive_EventArrived(ByVal sender As Object, 
                    ByVal e As System.Management.EventArrivedEventArgs) _
                    Handles Watcher.EventArrived

        If inEvent Then Exit Sub
        inEvent = True

        Dim col As Dictionary(Of String, Management.ManagementObject) = GetUSBDevices()

        Select Case col.Count
            Case Is > pnpCol.Count
                ' device arrived
                ProcessArrival(col)
            Case Is < pnpCol.Count
                ' device removed
                ProcessRemoval(col)
            Case Is = pnpCol.Count
                ' noise...this is a chatty rascal
        End Select

        inEvent = False

    End Sub

    Private Sub ProcessArrival(col As Dictionary(Of String,
               Management.ManagementObject))
        For Each kvp As KeyValuePair(Of String, 
                 Management.ManagementObject) In col
            If pnpCol.ContainsKey(kvp.Key) = False Then

                'Console.WriteLine("{0} {1} ", kvp.Key, kvp.Value)
                'DebugProperties(kvp.Value)

                Dim ea As New USBWatcherEventArgs(kvp.Value("DeviceID").ToString,
                                      SafeString(kvp.Value("VolumeName")),
                                      SafeString(kvp.Value("VolumeSerialNumber")))

                RaiseEvent DeviceAdded(Me, ea)

                'rebuild baseline for next event
                pnpCol = col

            End If
        Next

    End Sub

    Private Sub ProcessRemoval(col As Dictionary(Of String,
                    Management.ManagementObject))
        For Each kvp As KeyValuePair(Of String, 
                          Management.ManagementObject) In pnpCol
            If col.ContainsKey(kvp.Key) = False Then

                'Console.WriteLine("{0} {1} ", kvp.Key, kvp.Value)
                'DebugProperties(kvp.Value)

                Dim ea As New USBWatcherEventArgs(kvp.Value("DeviceID").ToString,
                                      SafeString(kvp.Value("VolumeName")),
                                      SafeString(kvp.Value("VolumeSerialNumber")))

                RaiseEvent DeviceRemoved(Me, ea)

                'rebuild baseline for next event
                pnpCol = col

            End If
        Next

    End Sub

    ' lots of things can be NOTHING depending on the manufacturer's
    ' attention to detail.  try to avoid NRE
    Private Function SafeString(obj As Object) As String

        If obj.GetType Is GetType(String) Then
            Return CType(obj, String)
        Else
            If obj IsNot Nothing Then
                Return obj.ToString
            Else
                Return "???"
            End If
        End If

    End Function

    ' debug tool to poll a management object to get the properties and values
    Private Sub DebugProperties(mo As Management.ManagementObject)

        For Each pd As PropertyData In mo.Properties
            If pd.Value IsNot Nothing Then
                Console.WriteLine("{0} {1}", pd.Name,
                                  If(pd.Value IsNot Nothing,
                                     pd.Value.ToString,
                                     "Nothing"))
            End If

        Next
    End Sub

End Class

How to Implement USBWatcher

' local variable to catch events
Private WithEvents watcher As USBWatcher

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    watcher = New USBWatcher
    watcher.StartWatching()     ' or add to a button click
    ' I DONT have it starting automatically when you create the watcher

End Sub

The Device Watcher runs on a different thread so if you want to post a notice to a control, you will have to use a delegate:

Delegate Sub AddListItem(text As String)
Private myDelegate As AddListItem = New AddListItem(AddressOf AddNewListItem)

Private Sub AddNewListItem(text As String)
    myListBox.Items.Add(text)
End Sub

Then from the Device Added event, for example:

Private Sub watcher_DeviceAdded(sender As Object, 
            e As USBWatcher.USBWatcherEventArgs) Handles watcher.DeviceAdded

    Console.Beep()

    Dim msg As String = String.Format("Drive {0} ({1})   {2}", 
                                       e.DriveLetter,
                                       e.VolumeName, "Inserted")
    If myListBox.InvokeRequired Then
        myListBox.Invoke(myDelegate, New Object() {msg})
    Else
        myListBox.Items.Add(msg)
    End If

End Sub

DeviceRemoved would be the same except "Removed" as the third param in the message text.

USBWatcher also has a StopWatching method to turn off the watcher for a time, and StartWatching to start and restart it. Your app should call StopWatching when the app ends to prevent COM errors; just add watcher.StopWatching in the form close event.

This does what you want - raise events when removable media is inserted and return the information about them - just not exactly how you wanted it. It uses tried and tested WMI rather than the Win8 method, which is as yet has only sparse documention on MSDN and would only work on Win8.

Answer 2

you can use WMI to detect, if pen drive is inserted. You have to add reference to the System.Management dll of dotnet framework.

you can get Devide Details as :

Public Function SerialNO(ByVal DriveNameWithColon As String) As String
    Dim disk As ManagementObject = New ManagementObject("win32_logicaldisk.deviceid='" + DriveNameWithColon + "'")
    disk.Get()
    Return disk("VolumeSerialNumber").ToString()
End Function

Answer 3

You can get PnPObject from the interface ID which will give you more device specific information.

public static IAsyncOperation<PnpObject> CreateFromIdAsync(
  PnpObjectType type, 
  string id, 
  IEnumerable<string> requestedProperties
)

seems pretty interesting fellah. You have few different options to specfy for PnpObjectType,

DeviceInterface | deviceInterface - The PnpObject represents a device interface.

DeviceContainer | deviceContainer - The PnpObject represents a device container.

Device | device -The PnpObject represents a device.

DeviceInterfaceClass | deviceInterfaceClass - The PnpObject represents a device interface class.

The id actually is interface id, which you already received.

Also note that you have list of properties you can ask for(requstedProperties argument): http://msdn.microsoft.com/en-us/library/hh464997.aspx#ListOfCanonicalProperties.

It's true that there's not too much for you, but don't be scared. There's a lot more of them: http://msdn.microsoft.com/en-us/library/ff553416.aspx

If you check devpkey.h, you can find interesting properties, such as:

• DEVPKEY_Device_DevType
• DEVPKEY_Storage_Removable_Media
• DEVPKEY_Storage_Portable
-

Some of the things are device specfc, some of not. You can get even more properties through devmgmt.msc(Details->Property). There's also bunch of stuff in the registry. The Unified device property model discusses this: http://msdn.microsoft.com/en-us/library/ff553515(v=vs.85).aspx

PnP api has following methods:

Await DeviceInformation.FindAllAsync()
Await Pnp.PnpObject.FindAllAsync(Pnp.PnpObjectType.DeviceContainer, ...)
Await Pnp.PnpObject.FindAllAsync(Pnp.PnpObjectType.Device, ...)
Await Pnp.PnpObject.FindAllAsync(Pnp.PnpObjectType.DeviceInterface, ...) 
Await Pnp.PnpObject.FindAllAsync(Pnp.PnpObjectType.DeviceInterfaceClass, ...)  
Await Pnp.PnpObject.CreateFromIdAsync(..., id, ...)

You can read this article: http://www.codeproject.com/Articles/458550/Device-enumeration-in-Windows

It has everything, source code, keys, and shows how to dump all the properties from devices into file. This way you can see what properties your USB stick has.