Data Validation in Silverlight

 public class User

 {

     public string Name

     {

         get { return name; }

         set

         {

             if ( string.IsNullOrEmpty( value ) )

             {

                 throw new Exception( "Please set a value" );

             }

             name = value;

         }

     }

    public bool Gender { ... }

     public string LikesSilverlight { ... }

    public string Attended { ... }

     public bool AcceptTerms { ... }

     private string name;

     private bool gender;

     private string likesSilverlight;

     private string attended;

     private bool acceptTerms;

 }

 <StackPanel>

     <StackPanel.DataContext>

        <local:User />

     </StackPanel.DataContext>

     <TextBlock Text="Registration Form" FontSize="16"/>

     <TextBlock Text="Name" />

     <TextBox Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True}"/>

     <TextBlock Text="Gender" />

     <StackPanel Orientation="Horizontal">

         <RadioButton GroupName="Gender" Content="Male" IsChecked="True" />

         <RadioButton GroupName="Gender" Content="Female" 

             IsChecked="{Binding Gender, Mode=TwoWay, ValidatesOnExceptions=True}" />

     </StackPanel>

     <TextBlock Text="I Like Silverlight" />

     <ComboBox x:Name="LikesSilverlightCombo" 

         SelectedItem="{Binding LikesSilverlight, Mode=TwoWay, 

                        ValidatesOnExceptions=True, UpdateSourceTrigger=Explicit}">

         <sys:String>Yes</sys:String>

         <sys:String>No</sys:String>

     </ComboBox>

     <TextBlock Text="I've attended" />

     <ListBox SelectionMode="Extended"

         SelectedItem="{Binding Attended, Mode=TwoWay, ValidatesOnExceptions=True}">

         <sys:String>None</sys:String>

         <sys:String>MIX 07</sys:String>

         <sys:String>MIX 08</sys:String>

         <sys:String>MIX 09</sys:String>

     </ListBox>

     <CheckBox x:Name="AcceptTermsCheckBox" Content="Accept Terms" 

         IsChecked="{Binding AcceptTerms, Mode=TwoWay, ValidatesOnExceptions=True}" />

     <Button Content="Register" Click="Validate" 

         IsEnabled="{Binding IsChecked, ElementName=AcceptTermsCheckBox}" />

 </StackPanel>

BindingExpression be = this.LikesSilverlightCombo.GetBindingExpression( ComboBox.SelectedItemProperty );

be.UpdateSource();