How to download from ftp without form lag vb.net - vb.net

Question

I just made a ftp chat in vb.net and it update message from a file from a ftp server
so i add a timer with interval 1000 with this code
Try
Dim client As New Net.WebClient
client.Credentials = New Net.NetworkCredential("fnet_1355****", "******")
RichTextBox1.Text = client.DownloadString("ftp://185.**.***.**/htdocs/chat­.txt")
Catch ex As Exception
End Try
so .. the file is downloaded and it update the text successful but there is a problem .. every time he download the form have a bit lag ... and i dont like that :D what i can do ?

Answer 1

RichTextBox1.Text = client.DownloadString("ftp://185.**.***.**/htdocs/chat­.txt")
Instead of this try async method.
client.DownloadStringAsync(new Uri("ftp://185.**.***.**/htdocs/chat­.txt"))
and then handle download string completed event.
Sample Code
client.DownloadStringAsync(new Uri("ftp://185.**.***.**/htdocs/chat­.txt"));
client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
void client_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
{
RichTextBox1.Text =e.Result;
}
You can also add progress indicator by handling progress change event.

Answer 2

The best way you can do it would be to use ThreadPool provided by the Framework to I/O bound operation on different thread.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf DownloadFromFtp))
End Sub
Private Sub DownloadFromFtp()
Try
Dim client As New Net.WebClient
client.Credentials = New Net.NetworkCredential("fnet_1355****", "******")
Dim response As String = client.DownloadString("ftp://185.**.***.**/htdocs/chat­.txt")
Me.Invoke(New MethodInvoker(Function() RichTextBox1.Text = response))
Catch ex As Exception
End Try
End Sub

Answer 3

This program was the exact one I design before i learned PHP.
Here try this:
Dim thrd As Threading.Thread
Dim tmr As New Timer
Dim tempstring As String
Private Sub thread_start()
thrd = New Threading.Thread(Sub() check_for_changes())
tmr.Interval = 50
AddHandler tmr.Tick, AddressOf Tick
tmr.Enabled = True
tmr.Start()
thrd.Start()
End Sub
Private Sub Tick(sender As Object, e As EventArgs)
If Not thrd.IsAlive Then
tmr.Stop() : tmr.Enabled = False
RichTextBox1.Text = tempstring
End If
End Sub
Private Sub check_for_changes()
Try
Dim client As New Net.WebClient
client.Credentials = New Net.NetworkCredential("fnet_1355****", "******")
tempstring = client.DownloadString("ftp://185.**.***.**/htdocs/chat­.txt")
Catch ex As Exception
End Try
End Sub
Hope It Helps.