The StringFormat on ToolTip bindings appear to be ignored. Does anyone have a means to format a ToolTip and access the DataContext of a DataPoint? Attached property, perhaps?
I'll try to dig up what I've done in this regard before, but the way I remember doing it is if the individual items in your data source have a property that creates whatever Tooltip visual you want. then you can use the DataMapping to indicate that the Tooltips are specified by that property in the DataSource.
-Graham
you may also want to see my answer here: http://forums.infragistics.com/forums/t/38424.aspx
for the Silverlight chart, but should still apply.