vb.net How can I show in each loop what thread is calculating and continue working in the form? - vb.net

Question

I have tried to make a loop inside a thread and, while it is showing me values in a textbox, continue working in my form.
The problem is, when it starts I can not do anything in the form, like pressing buttons or setting commands.
Here is the idea of code:
Imports System.Threading
Public Class Form1
Dim trd As System.Threading.Thread
Dim cont As Integer
Private Sub btnOpen_Click(sender As Object, e As EventArgs) Handles btnOpen.Click
cont = 0
trd = New Thread(AddressOf trdReadAxis)
trd.Start()
End Sub
Private Delegate Sub CloseFormCallback()
Private Sub trdReadAxis()
While cont < 10
If InvokeRequired Then
Dim d As New CloseFormCallback(AddressOf trdReadAxis)
Invoke(d, Nothing)
Else
txtXPosition.Text = cont
cont += 1
Thread.Sleep(1000)
End If
end while
end class
What can I do to see everi second the change in my textbox "txtXPosition"?
Thank you.

Answer 1

This code is a mess:
Private Sub trdReadAxis()
While cont < 10
If InvokeRequired Then
Dim d As New CloseFormCallback(AddressOf trdReadAxis)
Invoke(d, Nothing)
Else
txtXPosition.Text = cont
cont += 1
Thread.Sleep(1000)
End If
End while
End Sub
It looks like your worker thread calls itself back via Invoke, where it will execute on the UI thread. Once it is there, it goes through the entire while loop-- still on the UI thread-- with a Sleep(1000) in every iteration of the loop. This will lock out the message loop which is supposed to be handling your clicks and keystrokes.
I suggest you divide out the worker thread from the code that updates the textbox, like so:
Delegate SetTextCallBack(ByVal message as string)
Private Sub SetText(ByVal message as String)
if InvokedRequired then
Dim d As New SetTextCallback(AddressOf SetText)
Invoke(d, message)
Else
txtXPosition.Text = message
End If
end sub
Private Sub trdReadAxis()
While cont < 10
SetText cont
cont += 1
Thread.Sleep(1000)
End while
End Sub