<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="BindingWithFallback" Height="300" Width="300"> <StackPanel> <TextBox Text="{Binding Path=MyProperty, Mode=OneWay, FallbackValue=(waiting), IsAsync=True}" IsReadOnly="True" /> </StackPanel> </Window> //File:Window.xaml.cs using System; using System.Collections.Generic; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Shapes; namespace WpfApplication1{ class MyClass { public string MyProperty { get { System.Threading.Thread.Sleep(2000); return "BBB"; } } } public partial class Window1 : System.Windows.Window { public Window1() { InitializeComponent(); DataContext = new MyClass(); } } }