I have a DepencencyProperty (a boolean) that works fine on an Ellipse, but not on an ArcSegment.
Am I doing something that is not possible?
Here's part of
the xaml. Both
the TemplateBindings of Origin and LargeArc do not work in
the geometry. But
the LargeArc DependencyProperty does work in
the Ellipse, so my DependencyProperty seems to be set up correctly.
<ControlTemplate TargetType="{x:Type nodes:TestCircle}">
<Canvas Background="AliceBlue">
<Ellipse Height="10" Width="10" Fill="Yellow" Visibility="{TemplateBinding LargeArc, Converter={StaticResource BoolToVisConverter}}"/>
<Path Canvas.Left="0" Canvas.Top="0" Stroke="Black" StrokeThickness="3">
<Path.Data>
<GeometryGroup>
<PathGeometry>
<PathFigure IsClosed="True" StartPoint="{TemplateBinding Origin}">
<LineSegment Point="150,100" />
<ArcSegment Point="140,150" IsLargeArc="{TemplateBinding LargeArc}" Size="50,50" SweepDirection="Clockwise"/>
</PathFigure>
</PathGeometry>
</GeometryGroup>
</Path.Data>
</Path>
</Canvas>
</ControlTemplate>
What I'm trying to build is a (sort of) pie-shaped usercontrol where
the shape of
the Pie is defined by DependencyProperties and
the actual graphics used are in a template, so they can be replaced or customized.
In other words: I would like
the code-behind to be visual-free (which, I assume, is good separation).
SOLUTION--------------------------(I'm not allowed to answer my own questions yet)
I found
the answer myself, and this can be useful for others encountering
the same issue. This is why
the TemplateBinding on
the Geometry failed:
A TemplateBinding will only work when binding a DependencyProperty to another DependencyProperty.
Following article set me on
the right track: http://blogs.msdn.com/b/liviuc/archive/2009/12/14/wpf-templatebinding-vs-relativesource-templatedparent.aspx
The ArcSegment properties are no DependencyProperties.
Thus,
the solution to
the above problem is to replace
<ArcSegment Point="140,150" IsLargeArc="{TemplateBinding LargeArc}"
with
<ArcSegment Point="140,150" IsLargeArc="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=LargeArc}"
Colin, your working example where an 'ordinary' binding was used in
the geometry set me on
the right track.
BTW, love
the infographics and
the construction of your UserControl in your blogpost.
And, hey, that quick tip on code snippets, and especially on that DP attribute and
the separation of those DPs into a partial class file is pure gold!
