Adding Connecting Lines to Prevent Pie Overlapping

You can add connecting lines with the PlotElement.LabelLine Attached property like the following XAML code:

<c1:DataSeries.PointLabelTemplate>
  <DataTemplate>
    <Border BorderBrush="DarkGray" BorderThickness="1" Background="LightGray"
            c1:PlotElement.LabelAlignment="Auto"
            c1:PlotElement.LabelOffset="30,0">
      <TextBlock Text="{Binding Value, StringFormat=0}" />
      <c1:PlotElement.LabelLine>
        <Line Stroke="LightGray" StrokeThickness="2" />
      </c1:PlotElement.LabelLine>
    </Border>
  </DataTemplate>
</c1:DataSeries.PointLabelTemplate>

See Also

Adding Labels to Pie Charts