WM_DEVICECHANGE

[=?Utf-8?B?Sks=?=]

I need to load the contents of a file from a USB flash drive when it
inserted. Can someone please provide a sample of how this can be achieved?

[Newbie Coder]

Re: WM_DEVICECHANGE

I wrote this code a few weeks ago

Imports System.Runtime. InteropServices

#Region "Constants"

Private Const WM_DEVICECHANGE As Integer = &H219
Private Const DBT_DEVICEARRIV AL As Integer = &H8000
Private Const DBT_DEVICEREMOV ECOMPLETE As Integer = &H8004
Private Const DBT_DEVTYP_VOLU ME As Integer = &H2

#End Region

#Region "Structures "

Private Structure DEV_BROADCAST_H DR
Public dbch_size As Int32
Public dbch_devicetype As Int32
Public dbch_reserved As Int32
End Structure

Private Structure DEV_BROADCAST_V OLUME
Public dbcv_size As Int32
Public dbcv_devicetype As Int32
Public dbcv_reserved As Int32
Public dbcv_unitmask As Int32
Public dbcv_flags As Int32
End Structure

#End Region

#Region "WndProc (SUB)"

Protected Overrides Sub WndProc(ByRef m As Message)
' Windows MESSAGE
If m.Msg = WM_DEVICECHANGE Then
' Check to see if device was plugged in
If m.WParam.ToInt3 2() = DBT_DEVICEARRIV AL Then
Dim hdr As DEV_BROADCAST_H DR =
CType(Marshal.P trToStructure(m .LParam, GetType(DEV_BRO ADCAST_HDR)),
DEV_BROADCAST_H DR)
' See if the device is a USB Flash Drive etc.
If hdr.dbch_device type = DBT_DEVTYP_VOLU ME Then
' Declare volume as structure
Dim vol As DEV_BROADCAST_V OLUME =
CType(Marshal.P trToStructure(m .LParam, GetType(DEV_BRO ADCAST_VOLUME)) ,
DEV_BROADCAST_V OLUME)
' Get volume number
Dim mask As Int32 = vol.dbcv_unitma sk
' Get the drive letter
Dim chDriveLetter As Char() = GetDriveLetter( mask)
' Display the drive letter
lblDrive.Text = String.Format(" USB Flash Drive Plugged
Into {0}:", chDriveLetter(0 ).ToString().To Upper())
End If
ElseIf m.WParam.ToInt3 2() = DBT_DEVICEREMOV ECOMPLETE Then
' Flash Drive Unplugged
lblDrive.Text = "USB Flash Drive Removed"
End If
End If
MyBase.WndProc( m)
End Sub

#End Region

#Region "Get Drive Letter (FUNCTION)"

Private Function GetDriveLetter( ByVal iChar As Int32) As Char()
Dim cnt As Integer = 0
Dim intTemp As Int32 = iChar
Dim i As Integer

For i = 0 To 31
If (intTemp And 1) = 1 Then
cnt += 1
End If
intTemp = (intTemp >1)
If intTemp = 0 Then
Exit For
End If
Next

Dim chResult(0) As Char
Dim ii As Integer

For ii = 0 To 31
If (iChar And 1) = 1 Then
chResult(0) = Chr(97 + ii)
End If
iChar = (iChar >1)
If iChar = 0 Then
Exit For
End If
Next
Return chResult
End Function

#End Region

[Herfried K. Wagner [MVP]]

Re: WM_DEVICECHANGE

"JK" <JK@discussions .microsoft.coms chrieb:

>I need to load the contents of a file from a USB flash drive when it
inserted. Can someone please provide a sample of how this can be achieved?

<URL:http://www.vb-tips.com/dbpages.aspx?IA =NG>

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[=?Utf-8?B?Sks=?=]

RE: WM_DEVICECHANGE

Thank you both!

"JK" wrote:

I need to load the contents of a file from a USB flash drive when it
inserted. Can someone please provide a sample of how this can be achieved?