Hello Chris Thierry,
Due to the specifics of the legend control (we wanted the user to be able to add manually legend items even when the rest are auto-generated -- this is basically not supported out-of-the-box by the WPF/Silverlight control), you need to cast the ChartLegend to its base type to access the items like this (you can call this in the DataBound event handler for example):
Hope this helps.
All the best,
the Telerik team
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