WPF validation on mandatory field

Hi, I'm new to Wpf..i need to add black asterisks to all mandatory fields like ex: First name *,Last name*.....if user is trying to save the form without entering any mandatory fields then i have to display the respective filed in red color ie, respective labelname to be red along with asterisks ex: Field name *(including asterisks)..can some one help me on this:

Currently on xaml..i updated like this for showing mandatory fields

 <Label Content="First Name" HorizontalAlignment="Right" Grid.Column="0" VerticalAlignment="Center" Margin="0,1,33,2" Height="26" Width="67"/>

 <Label Name="lblVerificationFirstName" Content="*" Margin="0,2,18,0" HorizontalAlignment="Right" VerticalAlignment="Top" />

Please help me on validation part!