Private Sub btnDirectories_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDirectories.Click
        Dim drivestring As String = txtDrive.Text + ":\"
        Try
            listDirectories(drivestring)
        Catch ex As Exception
            MessageBox.Show("Invalid drive", "Tool", MessageBoxButtons.OK, MessageBoxIcon.Hand)
            MessageBox.Show("Exception thrown: " & ex.Message)
        End Try


    End Sub


    'Sub routine
    'Run on click of btnListDirectories
    '
    'Displays all directories on drive
    '
    'Args: drive as String, name of drive to search
    '
    'Populates list box lstDirectories
    '
    'Calls Function searchForFiles on each execution of loop


    Private Sub listDirectories(ByVal drive As String)
        'List each folder at the root of specified drive
        For Each strFolder As String In My.Computer.FileSystem.GetDirectories(drive)
            'Add the item to the list
            lstData.Items.Add(strFolder)
            If strFolder <> "d:\System Volume Information" Then

                'Search for books in directory
                'Me.lstBooks.Text = Me.SearchForFiles(strFolder, FileIO.SearchOption.SearchAllSubDirectories, "*.txt")


                Me.rtbTempBookList.Text = Me.SearchForFiles(strFolder, FileIO.SearchOption.SearchAllSubDirectories, "*.pdf")


            End If


        Next

        'Temporary message show number of returned files
        MessageBox.Show(tempCount)

    End Sub

    'Function
    'Run on each execution of loop in Sub listDirectories
    '
    'Displays all books, documents matching criteria
    '
    'Args: directory as string, name of directory to search
    '      searchOption as Microsoft.VisualBasic.FileIO.SearchOption, depth of search
    '      wildcards as string, any criterion the search needs to match
    '
    'Populates list box lstBooks
    '
    'Returns: returnValue as String, file names of files matching criteria  

    Protected Function SearchForFiles(ByVal directory As String, ByVal searchOption As Microsoft.VisualBasic.FileIO.SearchOption, ByVal wildCards As String) As String
        Dim returnValue As String = ""



        Try
            For Each foundFile As String In My.Computer.FileSystem.GetFiles(directory, searchOption, wildCards)
                returnValue &= foundFile & Environment.NewLine
                tempCount = tempCount + 1

            Next
        Catch ex As Exception
            MessageBox.Show("Exception thrown: " & ex.Message)
        End Try

        Return returnValue
    End Function