idataerrorinfo

You should modify the TextBox style so it shows what’s wrong with the property. Here is a simple example that shows the error as tooltip: <Style TargetType=”TextBox”> <Style.Triggers> <Trigger Property=”Validation.HasError” Value=”true”> <Setter Property=”ToolTip” Value=”{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors).CurrentItem.ErrorContent}” /> </Trigger> </Style.Triggers> </Style> Just put it inside Application.Resources from your app.xaml file and it will be aplied … Read more