Mulithreading in windows forms

Yes sir..but that articles are related with console applications..

You could do something like:

System.Threading.Tasks.Parallel.For(0, 100, i =>
        {
            listBox1.Items.Add(i)
            listBox2.Items.Add(i)
        });

But I will tell you up front that this answer is currently wrong because it will fail when it tries to access the listboxes because they will likely need to be accessed by using something like ...

Private Delegate Sub dlgListBox1Update(ByVal text As String)
 
Sub updateListBox1(ByVal text As String)
    If ListBox1.InvokeRequired = True Then
        Dim d As New dlgListBox1Update(AddressOf updateListBox1)
        ListBox1.Invoke(d, text)
    Else
        ListBox1.Items.Add(text)
    End If
End Sub

Private Delegate Sub dlgListBox2Update(ByVal text As String)
 
Sub updateListBox2(ByVal text As String)
    If ListBox2.InvokeRequired = True Then
        Dim d As New dlgListBox2Update(AddressOf updateListBox2)
        ListBox2.Invoke(d, text)
    Else
        ListBox2.Items.Add(text)
    End If
End Sub

System.Threading.Tasks.Parallel.For(0, 100, i =>
        {
            updateListBox1(i.toString)
            updateListBox2(i.toString)
        });

You need to use the delegates and the update subroutines in order to ensure that you adjust to the correct thread for actually updating the listboxes ... that's the fundamental challenge with multithreaded applications (and why most examples use the console so they can focus on the example and not creating delegates).

Of course the next problem you'll have is when you try and change variables within your different threads ... if you use global variables then you'll need to lock them to ensure you don't change them from multiple threads.

Hope this helps.