Multithreading doesn't work

Question

I\'m making a simple multithreading program to explain the working of threading. I want two counters counting on the same time but it doesn\'t work.

It only works if I u

Answer 1

The multithreading works perfectly, but you are not utilizing it. The only thing you're currently doing in the background thread is calling Invoke, which means that your thread will exit within a few milliseconds and then be discarded.

Once you call Invoke the execution of the teller1 or teller2 method is moved to the UI thread, meaning it will block the UI until its execution is finished. You should only invoke when you are to update the UI, and perform all iterations in the background thread.

Here's an example of how you can do it more properly:

Delegate Sub SetTeller1(ByVal Text As String)

Private Sub teller1()
    For i As Integer = 0 To 1000
        SetTeller1Text(i)
    Next
End Sub

Private Sub SetTeller1Text(ByVal Text As String)
    If Me.InvokeRequired Then
        Me.Invoke(New SetTeller1(AddressOf SetTeller1Text), Text)
    Else
        teller1Label.Text = Text
        Me.Refresh()
    End If
End Sub

For improved readability I changed for example Invoke(...) to Me.Invoke(...).

Also I'm not sure why you're calling Refresh() as it isn't necessary and will just cause extra redrawing of the entire container (guessing this is a form).