backgroundworker - How to dynamically create a background worker in VB.net

Question

I have a VB.net project which uses a background worker to do some stuff.

Now I want to expand the project to be able to do multiple stuff :)

A user can enter an URL in a textbox and when the user click on the parse button the program creates a new tabcontrol a outputs some data.

I use a hardcoded background worker for this.

But now I want to run multiple background workers to do this stuff so I can't rely on hard coding the background worker(s).

Is it possible to create background workers dynamically.

I just don't have any idea how to set this up since I think I need to set up the different methods and variables like:

Private bw As BackgroundWorker = New BackgroundWorker
bw.WorkerReportsProgress = True
bw.WorkerSupportsCancellation = True
AddHandler bw.DoWork, AddressOf bw_DoWork
AddHandler bw.ProgressChanged, AddressOf bw_ProgressChanged
AddHandler bw.RunWorkerCompleted, AddressOf bw_RunWorkerCompleted
bw.RunWorkerAsync()

Private Sub bw_DoWork(), Private Sub bw_RunWorkerCompleted() and Private Sub bw_ProgressChanged()

I think I need to declare the background workers in some sort of array like variable (list / dictionary)??? Other then that I have no idea how to tackle this.

Answer 1

Here is how

Public Class Form
    Private Workers() As BackgroundWorker
    Private NumWorkers = 0

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        NumWorkers = NumWorkers + 1
        ReDim Workers(NumWorkers)
        Workers(NumWorkers) = New BackgroundWorker
        Workers(NumWorkers).WorkerReportsProgress = True
        Workers(NumWorkers).WorkerSupportsCancellation = True
        AddHandler Workers(NumWorkers).DoWork, AddressOf WorkerDoWork
        AddHandler Workers(NumWorkers).ProgressChanged, AddressOf WorkerProgressChanged
        AddHandler Workers(NumWorkers).RunWorkerCompleted, AddressOf WorkerCompleted
        Workers(NumWorkers).RunWorkerAsync()
    End Sub

End Class

Then the handlers

Private Sub WorkerDoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs)
    ' Do some work
End Sub

Private Sub WorkerProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs)
    ' I did something!
End Sub

Private Sub WorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs)
    ' I'm done!
End Sub

Imagine multithreading could be so easy. This works great unless you have 1000's of workers. The sender argument in each handler can be used to check which worker is reporting progress etc..