show progress bar while retrieving data in a separate thread

 private async void ShowAssessmentDetails(Guid assessmentEventID, int sectionNumber)
        {

            //…
            spProgress.Visibility = Visibility.Visible;
            await Task.Factory.StartNew(() => GetCurrentSection(AssessmentEventID, sectionId, CurrentSection)).ContinueWith(

                t =>

                {

                    spProgress.Visibility = Visibility.Collapsed;

                },TaskScheduler.FromCurrentSynchronizationContext());
            // continue …    

        }
   private void GetCurrentSection(Guid assessmentEventID,int sectionId, int TotalNumberOfSection)

        {

            CurrentSectionContent = service.GetSectionDetails(assessmentEventID, sectionId, TotalNumberOfSection, CurrentAssetClassId);

            CurrentSectionContent.IsCurrentSection = true;

        }