vb net backgroundworker + progress bar

Question

i want to create automatic progress bar that will popped up when i ran my program..

my program has 6 function/sub which run query that took quite long time to completed, it's approximately around 1-2 minutes regarding input

i'm using backgroundworker to handle the threads and combine it with progressbar

here's my code

RunWorkerAsync

Private Sub ButtonX1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonX1.Click
    BackgroundWorker1.WorkerReportsProgress = True
    BackgroundWorker1.RunWorkerAsync()
End Sub

Do_work

Private Sub BackgroundWorker1_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork

    For i As Integer = 0 To 100000000
        create_tree()
        localtree()
        localfrek()
        create_combination()
        showresult()
        If i Mod 10000000 Then
            BackgroundWorker1.ReportProgress(i / 100)
        End If
    Next


End Sub

ProgressChanged

 Private Sub BackgroundWorker1_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
    ProgressBar1.Visible = True
    ProgressBar1.Value = e.ProgressPercentage
End Sub

RunWorkerCompleted

Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
    MessageBox.Show("Task completed!")
End Sub

the problem is

the the progress bar didn't popped up
the function stop before completion

for the second problem i think it because the for loop that i use in Do_work event

i don't know the elapsed time of each function that i have, so i use random integer number in for loop

can you please help me to correct my program? thank you very much.. :)

jmcilhinney jmcilhinney · Accepted Answer · 2014-04-22T05:48:11

Firstly, you should be setting the Visible property of the ProgressBar before you call RunWorkerAsync.

Secondly, you should be comparing i Mod 10000000 to something.

Thirdly, if i goes up to 10000000 then i / 100 is going to go beyond 100.

vb net backgroundworker + progress bar

1 Answers