Imports System.IO
Imports System.Runtime.InteropServices

Public Class Form1
    Private Const WM_DEVICECHANGE As Integer = &H219
    Private Const DBT_DEVICEARRIVAL As Integer = &H8000
    Private Const DBT_DEVTYP_VOLUME As Integer = &H2

    'Device information structure
    Public Structure DEV_BROADCAST_HDR
        Public dbch_size As Int32
        Public dbch_devicetype As Int32
        Public dbch_reserved As Int32
    End Structure
    'Volume information Structure
    Private Structure DEV_BROADCAST_VOLUME
        Public dbcv_size As Int32
        Public dbcv_devicetype As Int32
        Public dbcv_reserved As Int32
        Public dbcv_unitmask As Int32
        Public dbcv_flags As Int16
    End Structure
    '<<<< Function that gets the drive letter from the unit mask >>>>
    Private Function GetDriveLetterFromMask(ByRef Unit As Int32)
        Dim i As Integer
        For i = 0 To 25
            If Unit And i Then Exit For
            Unit = Unit >> 1
        Next
        Return Chr(i + Asc("A"))
    End Function

    'Override message processing to check for the DEVICECHANGE message
    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        If m.Msg = WM_DEVICECHANGE Then
            If m.WParam = DBT_DEVICEARRIVAL Then
                Dim DeviceInfo As DEV_BROADCAST_HDR
                DeviceInfo = Marshal.PtrToStructure(m.LParam, GetType(DEV_BROADCAST_HDR))
                If DeviceInfo.dbch_devicetype = DBT_DEVTYP_VOLUME Then
                    Dim Volume As DEV_BROADCAST_VOLUME
                    Volume = Marshal.PtrToStructure(m.LParam, GetType(DEV_BROADCAST_VOLUME))
                    Dim DriveLetter As String = (GetDriveLetterFromMask(Volume.dbcv_unitmask) & ":")
                    Dim Files() As String = Directory.GetDirectories(DriveLetter)
                    Dim filesnames() As String = Directory.GetFiles(DriveLetter)
                    Dim Filename As String
                    Dim file As String

                    For Each Filename In Files
                        ListView1.BeginUpdate()
                        ListView1.Items.Add(Filename)
                        ListView1.EndUpdate()
                        ListView1.Refresh()
                    Next
                    For Each file In filesnames
                        ListView1.BeginUpdate()
                        ListView1.Items.Add(file)
                        ListView1.EndUpdate()
                        ListView1.Refresh()
                    Next
                    'Dim di As DirectoryInfo = Directory.CreateDirectory(path)
                End If
            End If
        End If
        MyBase.WndProc(m)
    End Sub
End Class