Programming with .NET - General

Re: Nullable(Of T) Dependency Property Issues

StefanOlson — Mon, 20 Jul 2009 04:20:06 GMT

Yi-Lun Luo - MSFT:

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

Strictly speaking, it's Silverlight that doesn't support these types because the xaml in WPF does in fact support nullable types. The fact that Silverlight doesn't support them is frustrating.

...Stefan

Re: Nullable(Of T) Dependency Property Issues

Yi-Lun Luo - MSFT — Mon, 29 Sep 2008 05:27:15 GMT

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

Nullable(Of T) Dependency Property Issues

wjchristenson2 — Thu, 25 Sep 2008 19:18:57 GMT

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