In Silverlight 3, it appears that the AreaDataPoint template ignores any size set in its ControlTemplate.
<ControlTemplate TargetType="chartingTK:AreaDataPoint">
<Grid x:Name="Root" Opacity="1">
<!-- Width and Height are ignored -->
<Ellipse Width="75" Height="25"
StrokeThickness="{TemplateBinding BorderThickness}"
Stroke="OrangeRed"
Fill="{TemplateBinding Background}"/>
</Grid>
</ControlTemplate>
Does anybody know of a workaround?
One (partial) answer is to set the width and height of the datapoint in the style for the datapoint. For instance:
<chartingTK:AreaSeries.DataPointStyle>
<Style TargetType="Control">
<Setter Property="Height" Value="25" />
<Setter Property="Width" Value="25" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="chartingTK:AreaDataPoint">
<Grid x:Name="Root" Opacity="1">
<!-- Width and Height are no longer ignored, but will still be clipped at
the height and width set in the style above -->
<Ellipse Width="75" Height="25"
StrokeThickness="{TemplateBinding BorderThickness}"
Stroke="OrangeRed"
Fill="{TemplateBinding Background}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</chartingTK:AreaSeries.DataPointStyle>
Perhaps not optimal, but at least it's a starting point.