Updating UI with BackgroundWorker in WPF

Question

I am currently writing a simple WPF 3.5 application that utilizes the SharePoint COM to make calls to SharePoint sites and generate Group and User information. Since this pr

Answer 1

At first you need to support ProgressChanged events. Update your BackgroundWorker initialization to:

GroupListView.ItemSource = null;
mWorker = new BackgroundWorker();
mWorker.DoWork += new DoWorkEventHandler(worker_DoWork);
mWorker.WorkerSupportsCancellation = true;
mWorker.WorkerReportsProgress = true;
mWorker.ProgressChanged += OnProgressChanged;
mWorker.RunWorkerCompleted +=
        new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
mWorker.RunWorkerAsync(SiteURLTextBox.Text);

After that you have to add a OnProgressChanged handler:

private void OnProgressChanged(object sender, ProgressChangedEventArgs e)
{
    FetchDataProgressBar.Value = e.ProgressPercentage;
    ListViewItem toAdd = (ListViewItem)e.UserState;
    toAdd.MouseLeftButtonUp += item_MouseLeftButtonUp;
    GroupListView.Items.Add(toAdd);
}

Therefore you have to change your DoWork:

private void worker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
{
    BackgroundWorker worker = (BackgroundWorker)sender;            
    try
    {
        using (SPSite site = new SPSite((String)e.Argument))
        {
            SPWeb web = site.OpenWeb();
            SPGroupCollection collGroups = web.SiteGroups;
            if(GroupNames == null)
                GroupNames = new List();
            int added = 0;
            foreach(SPGroup oGroup in collGroups)
            {
                added++;
                ListViewItem tmp = new ListViewItem() {
                    Content = oGroup.Name
                };
                worker.ReportProgress((added * 100)/collGroups.Count,tmp);
            }
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show("Unable to locate a SharePoint site at: " + siteUrl);
    }
}

That's because you're not allowed to change GUI on DoWork.

After that, each ListViewItem is added separately to your ListView. I would also recommend, that your URL is passed as an argument to RunWorkerAsync.

Edit: Add percentage to OnProgressChanged.