MVVM progressbar and background worker visibility

Question

I'm using WPF MVVM and have a progress bar to report progress on a task, using background worker. It works except I'm having a problem if I make the progress bar collapsed when the work completes, if I do that the progress bar never gets to the end. If I leave the progress bar visible it's fine, but I don't want the progress bar to be visible when the task is finished. Can someone tell me where I'm going wrong? In the below GenerateOutput is just a function that creates some files and updates progress as it goes. ShowSummary() is something that needs to run when the task is finished. I tried putting a Thread.Sleep in the RunWorkerCompleted just so the user can actually see the completed bar before its collapsed but you still don't see it complete.

public void BackgroundWorkerGenerateOutputProgress()
    {
        ProgressVisibility = Visibility.Visible;
        BackgroundWorker worker = new BackgroundWorker();
        worker.DoWork += new DoWorkEventHandler(DoWork);
        worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(RunWorkerCompleted);
        worker.RunWorkerAsync();
    }

void DoWork(object sender, DoWorkEventArgs e)
    {
        if (IsInProgress)
            return;
        CurrentProgress = 0;
        IsInProgress = true;
        BackgroundWorker worker = sender as BackgroundWorker;
        GenerateOutput();
    }
void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        IsInProgress = false;
        ProgressVisibility = Visibility.Collapsed;
        ShowSummary();
    }

EDIT: I have changed it to the below, I'm still not seeing the progress bar get to the end:

public void BackgroundWorkerGenerateOutputProgress()
    {
        ProgressVisibility = Visibility.Visible;
        CurrentProgress = 0;
        BackgroundWorker worker = new BackgroundWorker();
        worker.WorkerReportsProgress = true;
        worker.DoWork += new DoWorkEventHandler(DoWork);
        worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(RunWorkerCompleted);
        worker.ProgressChanged += new ProgressChangedEventHandler(ProgressChanged);
        worker.RunWorkerAsync();
    }

    private void ProgressChanged(object sender,
        ProgressChangedEventArgs e)
    {
        CurrentProgress = e.ProgressPercentage;
    }
 void DoWork(object sender, DoWorkEventArgs e)
    {
        if (IsInProgress)
            return;
        IsInProgress = true;
        BackgroundWorker worker = sender as BackgroundWorker;

        DoIt(worker);
    }
    void DoIt(BackgroundWorker worker)
    {
        worker.ReportProgress(20);
        Thread.Sleep(1000);
        worker.ReportProgress(40);
        Thread.Sleep(1000);
        worker.ReportProgress(60);
        Thread.Sleep(1000);
        worker.ReportProgress(80);
        Thread.Sleep(1000);
        worker.ReportProgress(100);

    }
    void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {

        IsInProgress = false;
        ShowSummary();
        System.Threading.Thread.Sleep(2000);
        ProgressVisibility = Visibility.Collapsed;
    }

the xaml (sorry can't format):

<ProgressBar HorizontalAlignment="Left" Value="{Binding CurrentProgress, Mode=OneWay}" Height="20" Width="200" Visibility="{Binding Path=ProgressVisibility}" Minimum="0" Maximum="100" />

Answer 1

Try ReportProgress as shown in this link. You don't have WorkerReportsProgress = true

BackgroundWorker Class

If you are setting it at the end of GenerateOutput() then it is set to Visibility.Collapsed; before the UI is rendered.

Answer 2

I haven't tryied this but logically thinking I would do this apporch. Set the value of progress to its maxvalue before you hide it.

void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    CurrentProgress = 0; //Set this to max value
    IsInProgress = false;
    ProgressVisibility = Visibility.Collapsed;
    ShowSummary();
}