(XAML) Opdater form når data ændre sig løbende.

private void Button_Click(object sender, RoutedEventArgs e)
{
    var worker = new BackgroundWorker();
    worker.WorkerReportsProgress = true;
    worker.DoWork += worker_DoWork;
    worker.ProgressChanged += worker_ProgressChanged;
    worker.RunWorkerCompleted += worker_RunWorkerCompleted;
    worker.RunWorkerAsync();
}

void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    // kaldes i UI-tråden, når DoWork er færdig
    textblock.Text = "Færdig";
}

void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    // kaldes i UI-tråden, når ReportProgress kaldes fra DoWork-tråden
    textblock.Text = e.ProgressPercentage.ToString();
}

void worker_DoWork(object sender, DoWorkEventArgs e)
{
    // arbejde, som udføres i en anden tråd
    int count = 0;
    while (true)
    {
        (sender as BackgroundWorker).ReportProgress(count);
        Thread.Sleep(1000);
        if (++count == 11) break;
    }
}