Use BackgroundWorker to run task at background
<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="WPF" Height="100" Width="200"> <StackPanel> <ProgressBar Name="progressBar" Margin="4"/> <Button Name="button" Click="button_Click">Start</Button> </StackPanel> </Window> //File:Window.xaml.cs using System.ComponentModel; using System.Threading; using System.Windows; using System.Windows.Input; namespace WpfApplication1 { public partial class Window1 : Window { private BackgroundWorker worker = new BackgroundWorker(); public Window1() { InitializeComponent(); worker.WorkerReportsProgress = true; worker.DoWork += new DoWorkEventHandler(worker_DoWork); worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted); worker.ProgressChanged += worker_ProgressChanged; } private void button_Click(object sender, RoutedEventArgs e) { worker.RunWorkerAsync(); this.Cursor = Cursors.Wait; button.IsEnabled = false; } private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { this.Cursor = Cursors.Arrow; if(e.Error != null) MessageBox.Show(e.Error.Message); button.IsEnabled = true; } private void worker_DoWork(object sender, DoWorkEventArgs e) { for(int i = 1; i <= 100; i++) { Thread.Sleep(100); worker.ReportProgress(i); } } private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e) { progressBar.Value = e.ProgressPercentage; } } }