List files and folders vb.net

Hi nzfire;

Here is a solution using the new worker thread in .Net 2005. If you do not want to use a new thread then the code in BgWorker_DoWork and SearchFiles is the code to do what you want.

This code sample assumes that the form has the following controls on it:
TextBox called txtSearchPath
TextBox called txtSearchPattern
Label   called lblMessage
Button  called btnStart
ListBox called lstFiles


Imports System.IO

Public Class SearchFilesFrm

    ' To set up for a background operation, add an event handler for the DoWork event.
    ' Call your time-consuming operation in this event handler. To start the operation,
    ' call RunWorkerAsync. To receive notifications of progress updates, handle the
    ' ProgressChanged event. To receive a notification when the operation is completed,
    ' handle the RunWorkerCompleted event.
    ' Note  
    ' You must be careful not to manipulate any user-interface objects in your DoWork
    ' event handler. Instead, communicate to the user interface through the
    ' ProgressChanged and RunWorkerCompleted events.
    ' If your background operation requires a parameter, call RunWorkerAsync with your
    ' parameter. Inside the DoWork event handler, you can extract the parameter from
    ' the DoWorkEventArgs.Argument property.

    ' Store the results of the search
    Private Files As List(Of String)
    ' Used to prevent nested calls to ProgressChanged
    Private CallInProgress As Boolean
    ' The Worker thread
    Private WithEvents BgWorker As New System.ComponentModel.BackgroundWorker

    Private Sub SearchFilesFrm_Load(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles Me.Load

        ' Enable ProgressChanged and Cancellation mothed
        BgWorker.WorkerReportsProgress = True
        BgWorker.WorkerSupportsCancellation = True

    End Sub

    ' Start and Stop the search
    Private Sub btnStart_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles btnStart.Click

        If btnStart.Text = "Start" Then
            If Not Directory.Exists(txtSearchPath.Text.Trim()) Then
                MessageBox.Show("The Search Directory does not exist", _
                    "Path Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If
            If txtSearchPattern.Text.Trim() = "" Then txtSearchPattern.Text = "*"
            Dim arguments() As String = {txtSearchPath.Text.Trim(), _
                txtSearchPattern.Text.Trim()}

            lstFiles.Items.Clear()
            ' Start the background worker thread. Thread runs in DoWork event.
            BgWorker.RunWorkerAsync(arguments)
            btnStart.Text = "Stop"
        Else
            BgWorker.CancelAsync()
        End If

    End Sub

    ' Start the Asynchronous file search. The background thread does it work from
    ' this event.
    Private Sub BgWorker_DoWork(ByVal sender As Object, _
        ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BgWorker.DoWork

        'Retrieve the search path which was requested
        Dim path As String = DirectCast(e.Argument, String())(0)
        Dim pattern As String = DirectCast(e.Argument, String())(1)

        ' Invoke the worker procedure
        Files = New List(Of String)
        SearchFiles(path, pattern)
        ' Return a result to the RunWorkerCompleted event
        Dim message As String = String.Format("Found {0} Files", Files.Count)
        e.Result = message

    End Sub

    ' Recursively search directory and sub directories
    Private Sub SearchFiles(ByVal path As String, ByVal pattern As String)

        ' Displat message
        Dim message As String = String.Format("Parsing Directory {0}", path)
        BgWorker.ReportProgress(0, message)

        'Read the files and if the Stop button is pressed cancel the operation
        For Each fileName As String In Directory.GetFiles(path, pattern)
            If BgWorker.CancellationPending Then Return
            Files.Add(fileName)
        Next
        For Each dirName As String In Directory.GetDirectories(path)
            If BgWorker.CancellationPending Then Return
            SearchFiles(dirName, pattern)
        Next

    End Sub

    ' The bacground thread calls this event when you make a call to ReportProgress
    ' It is OK to access user controls in the UI from this event.
    ' If you use a Progress Bar or some other control to report the tasks progress
    ' you should avoid unnecessary calls to ReportProgress method because this causes
    ' a thread switch which is a relatively expensive in terms of processing time.
    Private Sub BgWorker_ProgressChanged(ByVal sender As Object, _
        ByVal e As System.ComponentModel.ProgressChangedEventArgs) _
        Handles BgWorker.ProgressChanged

        ' Reject a nested call.
        If CallInProgress Then Return
        CallInProgress = True
        ' Display the message received in the UserState property
        lblMessage.Text = e.UserState.ToString()
        ' Display all files added since last call.
        For idx As Integer = lstFiles.Items.Count To Files.Count - 1
            lstFiles.Items.Add(Files(idx))
        Next
        ' If a Me.Refresh is in this code you will need to place a Application.DoEvents()
        ' otherwise the UI will not respond without them it works fine.
        ' Me.Refresh()
        ' Let the Windows OS process messages in the queue
        ' Application.DoEvents()
        CallInProgress = False

    End Sub

    ' The background thread calls this event just before it reaches the End Sub
    ' of the DoWork event. It is OK to access user controls in the UI from this event.
    Private Sub BgWorker_RunWorkerCompleted(ByVal sender As Object, _
        ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) _
        Handles BgWorker.RunWorkerCompleted

        ' Display the last message and reset the Start/Stop button text
        lblMessage.Text = e.Result.ToString()
        btnStart.Text = "Start"

    End Sub

End Class


Fernando