The ChartDataSource does not provide grouping and that is why you will have to implement it yourself.
I have attached a sample project where you can see an example of that.
To use the demonstrated approach in your project, you can copy-paste the AggregateFunctions<T>
class and the GroupData<T>
method. To use them you need to call GroupData<T> method where T is your business class, the first parameter is a collection of data that has to be grouped, the next is parameter is where you specify the aggregate function, the next two are where you specify the value property and the category property and the last is where the property by which you want to group is.
I hope this helps.
the Telerik team