To anyone who is smarter than I am when it comes to WMI:
Here is what I am trying to do:
1) Detect a USB pen drive when it is inserted
2) Retrieve the drive letter of the pen drive
3) Check for a specific folder on the pen drive
I keep receiving an error message that reads:
An unhandled exception of type 'System.Executi onEngineExcepti on'
occurred in system.manageme nt.dll
The detection of the USB drive is working correctly, and it calls a
method called Arrival(). Within that method I call a CheckDrive()
method that is supposed to loop through all of the logical disks and
find a removable drive that contains a specific folder. I have also
gotten a System.Executio nEngineExceptio n when the application gets to
the following line of code:
Dim moc As ManagementObjec tCollection = disks.GetInstan ces()
I have also received a "Catastroph ic Failure" message when this
same code is used in another conceptual application I wrote.
Is there a better way to do this, maybe I am going about it the wrong
way. Any help would be greatly appreciated.
Here is my code, I am using the DotNetFramework 1.1:
Imports System.Runtime. InteropServices
Imports System.Windows. Forms
Imports System.Text
Imports System.manageme nt
Imports System.IO
Public Class DetectorForm
Inherits System.Windows. Forms.Form
#Region " Windows Form Designer generated code "
Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeCompo nent()
'Add any initialization after the InitializeCompo nent() call
RegisterHidNoti fication()
End Sub
'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As
Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Disp ose()
End If
End If
MyBase.Dispose( disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.Componen tModel.IContain er
'NOTE: The following procedure is required by the Windows Form
Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnos tics.DebuggerSt epThrough()> Private Sub
InitializeCompo nent()
'
'DetectorForm
'
Me.AutoScaleBas eSize = New System.Drawing. Size(5, 13)
Me.ClientSize = New System.Drawing. Size(440, 333)
Me.Name = "DetectorFo rm"
Me.Text = "DetectorFo rm"
End Sub
#End Region
Private Sub Arrival()
MsgBox("Arrival ")
CheckDrive()
End Sub
Private Sub Removal()
MsgBox("Removal ")
End Sub
Public Sub CheckDrive()
Try
Dim disks As New ManagementClass ("Win32_Logical Disk")
Dim moc As ManagementObjec tCollection =
disks.GetInstan ces()
Dim mo As ManagementObjec t
Dim DiskProperties As PropertyDataCol lection
Dim DiskProperty As PropertyData
Dim removableDisk As ManagementObjec t
'For each LogicalDisk on the Computer
For Each mo In moc
'Retrieve the disk's properties
DiskProperties = mo.Properties
'Iterate through the disk's properties
For Each DiskProperty In DiskProperties
'Check whether the particular property is defined
for this drive
If Not IsNothing(DiskP roperty.Value) Then
'Check if the drive is removable DriveType=2 -
Removable
If DiskProperty.Na me.ToString = "DriveType" _
And DiskProperty.Va lue.ToString = "2" Then
'Check if this Removable disk is a Zoom
Drive
Dim drvLetter As String
drvLetter =
mo.Properties(" DeviceId").Valu e.ToString()
'Check if a directory exists
If Directory.Exist s(drvLetter &
"chadc3322" ) Then
MsgBox("chadc33 22 Exists")
Exit For
End If
End If
End If
Next
Next mo
disks.Dispose()
Catch ex As Exception
MsgBox(ex.Messa ge)
End Try
End Sub
Public Sub RegisterHidNoti fication()
Dim dbi As DeviceDetector. DEV_BROADCAST_D EVICEINTERFACE = New
DeviceDetector. DEV_BROADCAST_D EVICEINTERFACE
Dim size As Integer
size = Marshal.SizeOf( dbi)
Dim gd As Guid
' MsgBox(Marshal. SizeOf(gd))
' MsgBox(Marshal. SizeOf(New
Win32.DEV_BROAD CAST_DEVICEINTE RFACE))
dbi.dbcc_size = size
dbi.dbcc_device type = DeviceDetector. DBT_DEVTYP_DEVI CEINTERFACE
dbi.dbcc_reserv ed = 0
dbi.dbcc_classg uid = DeviceDetector. GUID_IO_MEDIA_A RRIVAL
Dim Buffer As IntPtr
Buffer = Marshal.AllocHG lobal(size)
Marshal.Structu reToPtr(dbi, Buffer, True)
Dim r As IntPtr
r = DeviceDetector. RegisterDeviceN otification(Han dle, Buffer,
DeviceDetector. DEVICE_NOTIFY_W INDOW_HANDLE)
Marshal.PtrToSt ructure(Buffer, dbi)
If r.ToInt32 = IntPtr.Zero.ToI nt32 Then
'MessageBox.Sho w(DeviceDetecto r.GetLastError( ).ToString())
End If
End Sub
Protected Overrides Sub WndProc(ByRef m As Message)
If m.Msg = DeviceDetector. WM_DEVICECHANGE Then
OnDeviceChange( m)
End If
MyBase.WndProc( m)
End Sub
Private Sub OnDeviceChange( ByVal msg As Message)
Dim wParam As Integer
wParam = msg.WParam.ToIn t32()
If wParam = DeviceDetector. DBT_DEVICEARRIV AL Then
Dim o As New DeviceDetector. DEV_BROADCAST_H DR
Dim b As New DeviceDetector. DEV_BROADCAST_D EVICEINTERFACE1
Dim gd As Guid
Marshal.PtrToSt ructure(msg.LPa ram, o)
If (o.dbcc_devicet ype =
DeviceDetector. DBT_DEVTYP_DEVI CEINTERFACE) Then
Dim strsize As Integer = (o.dbcc_size - 28) / 2
ReDim b.dbcc_name(str size)
Marshal.PtrToSt ructure(msg.LPa ram, b)
Dim str As New String(b.dbcc_n ame, 0, strsize)
'************** *************** *************** ***
' Device Arrival
'************** *************** *************** ***
Arrival()
End If
ElseIf wParam = DeviceDetector. DBT_DEVICEREMOV ECOMPLETE Then
'************** *************** *************** ***
' Device Removal
'************** *************** *************** ***
Removal()
End If
End Sub
Private Class DeviceDetector
Public Const WM_DEVICECHANGE = &H219
Public Const DBT_DEVICEARRIV AL = &H8000
Public Const DBT_DEVICEREMOV ECOMPLETE = &H8004
Public Const DEVICE_NOTIFY_W INDOW_HANDLE = 0
Public Const DEVICE_NOTIFY_S ERVICE_HANDLE = 1
Public Const DBT_DEVTYP_DEVI CEINTERFACE = 5
Public Shared GUID_IO_MEDIA_A RRIVAL As Guid = New
Guid("A5DCBF10-6530-11D2-901F-00C04FB951ED")
<StructLayout(L ayoutKind.Seque ntial)> _
Public Class DEV_BROADCAST_D EVICEINTERFACE
Public dbcc_size As Integer
Public dbcc_devicetype As Integer
Public dbcc_reserved As Integer
Public dbcc_classguid As Guid
Public dbcc_name As Short
End Class
<StructLayout(L ayoutKind.Seque ntial, CharSet:=CharSe t.Unicode)>
_
Public Class DEV_BROADCAST_D EVICEINTERFACE1
Public dbcc_size As Integer
Public dbcc_devicetype As Integer
Public dbcc_reserved As Integer
<MarshalAs(Unma nagedType.ByVal Array,
ArraySubType:=U nmanagedType.U1 , SizeConst:=16)> _
Public dbcc_classguid( ) As Byte
<MarshalAs(Unma nagedType.ByVal Array, SizeConst:=128) > _
Public dbcc_name() As Char
End Class
<StructLayout(L ayoutKind.Seque ntial)> _
Public Class DEV_BROADCAST_H DR
Public dbcc_size As Integer
Public dbcc_devicetype As Integer
Public dbcc_reserved As Integer
End Class
<DllImport("use r32.DLL", SetLastError:=T rue)> _
Public Shared Function _
RegisterDeviceN otification(ByV al IntPtr As IntPtr, ByVal
NotificationFil ter As IntPtr, ByVal Flags As Int32) As IntPtr
End Function
<DllImport("ker nel32.DLL")> _
Public Shared Function _
GetLastError() As Integer
End Function
End Class
End Class
