[2005] Need advice (Multi threading)

[michaelrawi]

I recently start learning about multi threading. I'd want to know is my code right or wrong.

Public Class Form1
 
    Private Delegate Sub SetTextCallBack(ByVal val As Integer)
    Dim t As Threading.Thread
    Dim i As Integer = 0
 
    Private Sub SetText(ByVal val As Integer)
        If Me.Label1.InvokeRequired Then
            Dim d As New SetTextCallBack(AddressOf SetText)
 
            'I have used Me.Label1.begininvoke; Me.Label1.invoke; Me.begininvoke; Me.invoke
            'The result is same
            'The only difference is if doloop didn't sleep, begininvoke will stop responding
            'Me.BeginInvoke(d, val)
            Me.Invoke(d, val)
        Else
            Label1.Text = val
        End If
    End Sub
 
    Private Sub doLoop()
        While i < 10000
            If i > 9000 Then
                i = 0
            End If
 
            If i Mod 100 = 0 Then
                Me.SetText(i)
                Threading.Thread.Sleep(100)
            End If
 
            i += 1
        End While
 
        MessageBox.Show("Finished")
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Me.doLoop()
 
        t = New Threading.Thread(New Threading.ThreadStart(AddressOf doLoop))
        t.Start()
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        't.Abort() 'I've read some article that I should not use this.
        'Me.Text = "Button2"
        i = 10000
        t.Join() 'Or use t=nothing
    End Sub
End Class

My question is: Does this code right? It seems that doloop procedure must sleep for a while if I want my UI thread keep responding.

[jmcilhinney]

The whole point of using multi-threading in most cases is that the UI will continue to respond while the background operation takes place. That said, if the background operation is extremely intensive then your UI may still not get much of a look in, especially on single-processor systems.