How to update the ProgressBar in the main form using a thread?

[danyeungw]

I dropped a ProgressBar on a form. In the form button_click event, it uses a thread to update the ProgressBar. Please the code below. In the Worker1 class, Console.Write("A") worked but not objForm.ProgressBarMeter1.Value = i which means the ProgressBar did not updated. Any suggestion how the ProgressBar can be updated? Thanks.

Public Class FormLab11
Private Sub ButtonStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonStart.Click
Dim objWorker1 As New Worker1
Dim objWorker2 As New Worker2
Dim t1 As Thread
Dim t2 As Thread
t1 = New Thread(AddressOf objWorker1.Meter1)
t2 = New Thread(AddressOf objWorker2.Meter2)
t1.Start()
t2.Start()
Do While t1.IsAlive
t2.Join()
Loop
End Sub
End Class
 
Public Class Worker1
Public Sub Meter1()
Dim objForm As New FormLab11
For i As Integer = 0 To 10000
objForm.ProgressBarMeter1.Value = i
Console.Write("A")
Thread.Sleep(1)
Next
End Sub
End Class

Thanks.
DanYeung

 

[cjard]

In .net2 we would do heavy, or long running ops using a background worker. You dont have that in .net 1.1 but you could try this:

http://www.vsdotnet.be/blogs/tommer/2004/02/16/BackgroundWorkerForNETFramework11.aspx

 

[danyeungw]

I forgot to mentioned that my example is using .net 2. How does it in .net 2? Thanks.

DanYeung

 

[JohnH]

In .Net 2 as cjard said the BackgroundWorker class is easiest to work with for asynchronous operations.

Else with regular threads you have to invoke a delegated method on the thread that created the control to make thread-safe calls on it, usually the main thread.

Best way when you have no knowledge is to read a book chapter and lots of tutorials on the topic then dig into the documentation reference when you know what to read up on specifically.

 

[jmcilhinney]

If .NET 2.0 is your main platform can you please change your profile to reflect that. If your question relates to a version other thna your main platform please always specify.