Hi Igor,
The reason for this behavior is in the ChartYearGroupDescriptor and ChartMonthGroupDescriptor used. When grouping items each bar no longer represents a single data item (i.e. an object from the underlying data). In this case you may have an object for every day or even for every hour, but RadChart will display a single bar for the entire month, showing the sum of all items. When grouping, the
DataItem is actually a generic list of
KeyValue pairs, where each pair's key is the GroupDescriptor's member and the value is the actual value for the group. Knowing that you have added ChartYearGroupDescriptor and ChartMonthGroupDescriptor you can attach to the
ItemDatabound event and compose the tooltip:
You can find a small example attached.
All the best,
Evgenia
the Telerik team
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