.NET 5 BGW Never Finishes in Prod Only

[dday9]

The way the program works is that the user can choose one or more items from a listbox. They then press a button. For each item selected, a BackGroundWorker is launched to get data from a service for that item.

This is a code smell. Why not start one background worker and loop over each item? If you want them to be processed simultaneously you would leverage a parallelism paradigm. What I suspect is happening is that one or more background workers are failing and so your form variable never reaches 0.

Reading your post a bit more, this plays into your suspicion as to what is happening.

With that being said, what are you doing in terms of error handling? Because if one of the workers fail, then I would suspect one of two things to happen:

1. The entire process is stopped and the user is notified
2. One "batch" doesn't stop the process, but it still decreases form variable value.

Update
So for example, if you were to setup your background worker to do the following:

Private Sub MyBackgroundWorker_DoWork(sender As Object, e As DoWorkEventArgs) Handles MyBackgroundWorker.DoWork
    For counter As Integer = 0 To SelectedItems.Length - 1
        Dim failedRequest As Object = Nothing
        Try
            ' do something with the item
        Catch ex As Exception
            failedRequest = SelectedItems(counter)
        Finally
            MyBackgroundWorker.ReportProgress(100 * counter / SelectedItems.Length, failedRequest)
        End Try
    Next
End Sub

Private Sub MyBackgroundWorker_ProgressChanged(sender As Object, e As ProgressChangedEventArgs) Handles MyBackgroundWorker.DoWork
    If (e.UserState IsNot Nothing) Then
        ' e.UserState failed, do something (or not)
    End If
End Sub