multithreading not working?

[rbreidenstein]

I am attempting to learn how to multithread and i am making this as a simple sample.

but it doesn't work, the threads run one after the other instead of thread2 completing before thread1.

any suggestions?

Imports System.Threading
Public Class Form1
    Public Delegate Sub StepProgressBar()

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim Thread1 As System.Threading.Thread
        Dim Thread2 As System.Threading.Thread
        ProgressBar1.Value = 0
        ProgressBar2.Value = 0
        ProgressBar1.Maximum = 9999
        ProgressBar2.Maximum = 999

        ProgressBar1.Step = 1
        ProgressBar2.Step = 1

        Thread1 = New System.Threading.Thread(AddressOf Run1)
        Thread2 = New System.Threading.Thread(AddressOf Run2)

        Thread1.Start()
        Thread2.Start()
    End Sub
    Sub stepBar2()
        Dim _step2counter As Integer = 0

        _step2counter = 0
        Do While _step2counter <= ProgressBar2.Maximum

            ProgressBar2.PerformStep()
            _step2counter += 1

        Loop
    End Sub
    Sub stepBar1()
        Dim _step1Counter As Integer = 0

        Do While _step1Counter <= ProgressBar1.Maximum

            ProgressBar1.PerformStep()

            _step1Counter += 1
            Thread.Sleep(0)
        Loop
    End Sub

    Sub Run1()
        ProgressBar1.Invoke(New StepProgressBar(AddressOf stepBar1))
        ' ProgressBar1.Invoke(New StepProgressBar(AddressOf stepBar), New _
        '  Object() {1})
        'Me.ProgressBar1.PerformStep()
    End Sub

    Sub Run2()
        ProgressBar2.Invoke(New StepProgressBar(AddressOf stepBar2))
        ' ProgressBar2.Invoke(New StepProgressBar(AddressOf stepBar), New _
        'Object() {1})
        ' Me.ProgressBar2.PerformStep()
    End Sub
End Class

 

[jmcilhinney]

You're telling Thread1 to sleep for zero time so it won't sleep at all. Also, what's the point of the _step1counter and _step2Counter variables? Surely you should be testing the Value property of the ProgressBars against their Maximums.

 

[rbreidenstein]

i got it to work, in the code i was actually telling a thread to sleep but not the acutally thread i wanted. thread.sleep(0) means to pass any remaining time to the next thread.

 

[jmcilhinney]

thread.sleep(0) means to pass any remaining time to the next thread.

That I didn't know. You live and learn.