I am trying to create dependency properties that utilize the Nullubale(Of T) structure.  When I set the property in XAML, I get parser exceptions.

For instance, I have a user control and I may or may not want to set its color.  If I don't set its color, I want t auto-color it using a predefined color.  This would be easy using the Nullable(Of T) structure because I could simply do a test on the property like so: Me.Color.HasValue.  I've tried explicitly defining a type converter attribute on my properties to no avail.  Any ideas?

    Public Shared ReadOnly ColorProperty As DependencyProperty = DependencyProperty.Register("Color", GetType(Nullable(Of Color)), GetType(Series), Nothing)

    <ComponentModel.TypeConverterAttribute(GetType(Nullable(Of Color)))> _
    Public Property Color() As Nullable(Of Color)
        Get
            Return CType(GetValue(Series.ColorProperty), Nullable(Of Color))
        End Get
        Set(ByVal value As Nullable(Of Color))
            SetValue(Series.ColorProperty, value)
        End Set
    End Property

Unfortunately XAML doesn't support Nullable types because they're generic types...

shanaolanxing - I'll transfer to the Windows Azure team, and will have limited time to participate in the Silverlight forum. Apologize if I don't answer your questions in time.