Coerce a WPF TextBox not working anymore in .NET 4.0
Try using in xaml Explicit instead of PropertyChanged: <TextBox Text=”{Binding Percentage, Mode=TwoWay, UpdateSourceTrigger=Explicit, TargetNullValue={x:Static System:String.Empty}}” TextChanged=”TextBox_TextChanged” /> and in code behind UpdateSource instead of UpdateTarget private void TextBox_TextChanged(object sender, TextChangedEventArgs e) { // Removed safe casts and null checks ((TextBox)sender).GetBindingExpression(TextBox.TextProperty).UpdateSource(); } Tested it and it works. Btw this problem will probably be resolved in a … Read more