You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.
You write the following code segment.
public class Contact { private string _contactName;
public string ContactName {
get { return _contactName; }
set {
if (string.IsNullOrEmpty(value))
throw new ApplicationException(“Contact name is required”);
_contactName = value;
}
}
}
You add the following code fragment in a WPF window control.
<TextBox Text=”{Binding Path=ContactName, ValidatesOnExceptions=True, UpdateSourceTrigger=PropertyChanged}” />
The TextBox control is data-bound to an instance of the Contact class. You plan to implement an ErrorTemplate in the TextBox control.
You need to ensure that the validation error message is displayed next to the TextBox control. Which code fragment should you use?

A.
<ControlTemplate>
<DockPanel>
<AdornedElementPlaceholder Name=”box” />
<TextBlock Text=”{Binding ElementName=box, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}” Foreground=”Red” />
</DockPanel>
</ControlTemplate>

B.
<ControlTemplate>
<DockPanel>
<AdornedElementPlaceholder Name=”box” />
<TextBlock Text=”{Binding ElementName=box, Path=(Validation.Errors)[0].Exception.Message}” Foreground=”Red” />
</DockPanel>
</ControlTemplate>

C.
<ControlTemplate>
<DockPanel>
<ContentControl Name=”box” />
<TextBlock Text=”{Binding ElementName=box, Path=ContentControl.(Validation.Errors)[0].ErrorContent}” Foreground=”Red” />
</DockPanel>
</ControlTemplate>

D.
<ControlTemplate>
<DockPanel> <ContentControl Name=”box” />
<TextBlock Text=”{Binding ElementName=box, Path=(Validation.Errors)[0].Exception.Message}” Foreground=”Red” />
</DockPanel>
</ControlTemplate>