support shadow assist on colour zones

Author: ButchersBoy

MainDemo.Wpf/ColorZones.xaml

@@ -78,7 +78,7 @@
                 </StackPanel>
             </wpf:ColorZone>
             <TextBlock Margin="0 16 0 0" FontSize="10">Add in a corner radius and shadow.</TextBlock>
-            <wpf:ColorZone Mode="PrimaryDark" Padding="16" CornerRadius="3" Effect="{DynamicResource MaterialDesignShadowDepth3}" Margin="2">
+            <wpf:ColorZone Mode="PrimaryDark" Padding="16" CornerRadius="3" wpf:ShadowAssist.ShadowDepth="Depth3" Margin="2">
                 <StackPanel Orientation="Horizontal">
                     <ToggleButton Style="{DynamicResource MaterialDesignHamburgerToggleButton}" />
                     <TextBlock VerticalAlignment="Center" Margin="16 0 0 0">Material Design In XAML Toolkit</TextBlock>

MaterialDesignThemes.Wpf/Converters/ShadowConverter.cs

@@ -30,6 +30,8 @@ static ShadowConverter()
 
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
+            if (!(value is ShadowDepth)) return null;
+
             return ShadowsDictionary[(ShadowDepth) value];
         }
 

MaterialDesignThemes.Wpf/Themes/Generic.xaml

@@ -354,14 +354,15 @@
         <Setter Property="HorizontalContentAlignment" Value="Stretch" />
         <Setter Property="VerticalAlignment" Value="Top" />
         <Setter Property="IsTabStop" Value="False" />
+        <Setter Property="Effect" Value="{Binding RelativeSource={RelativeSource Self}, Path=(local:ShadowAssist.ShadowDepth), Converter={x:Static converters:ShadowConverter.Instance}}" />
         <Setter Property="Template">
             <Setter.Value>
                 <ControlTemplate TargetType="{x:Type local:ColorZone}">
                     <Border Background="{TemplateBinding Background}"
                             BorderBrush="{TemplateBinding BorderBrush}"
                             BorderThickness="{TemplateBinding BorderThickness}"
                             CornerRadius="{TemplateBinding CornerRadius}"
-                            ClipToBounds="True"
+                            ClipToBounds="True"                            
                             >
                         <ContentPresenter Content="{TemplateBinding Content}"
                                           ContentTemplate="{TemplateBinding ContentTemplate}"