Having clear button set value to null?

[Rick Glos]

When I hit the clear button, it's sets the value to an empty string.  Can I have it set the value to null if I'm binding to a Nullable?

[Rick Glos]

I've accomplished it for now using a Converter.

<telerik:RadMaskedTextInput Grid.Row="7" Grid.Column="1" Value="{Binding Path=Shareholder.TaxIdSecondary, Mode=TwoWay, Converter={StaticResource RadMaskedTextInputStringToNullConverter}, NotifyOnValidationError=True, ValidatesOnDataErrors=True}" IsEnabled="{Binding IsEditMode}" Margin="5" EmptyContent="Secondary Tax ID" Mask="###-##-####" TextMode="MaskedText" SelectionOnFocus="SelectAll" InputBehavior="Replace"></telerik:RadMaskedTextInput>

// This converter is to allow for setting the value to null when the user clicks the clear button on the RadMaskedTextInput

public class RadMaskedTextInputStringToNullConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return value;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        // if value is a string and it's empty, return null
        if (value.GetType() == typeof(string))
        {
            var valueAsString = value as string;
            if (string.IsNullOrEmpty(valueAsString))
            {
                return null;
            }
        }

        // otherwise just return the value
        return value;
    }
}