I try to explain more accurately the request.

Suppose that we know that a series dataset is ordered respect X.
If is, every procedure that search points closer to an X point can be extremely efficient.
In example, this happens drawing trackbals or showing labels and perhaps determining the points subset for a X pan/zoom.

Now, chart can choose to use efficient search alghoritms only if dataset is ordered.
I purposed three possible solution about this:

1) Declarative. Developer declare that a Series Dataset is ordered using a new series property. In Example IsPointsXOrdered = [None (default), Asc, Desc]. I the property is set Asc or Desc chart can use efficient alghoritms.

2) Automatic: If the same property can assume the "Automatic" value, additing/moving points in datase start a subroutine that determine if dataset is ordered or not. This solution can be extremely expensive and I don't suggest it.

3) Programming. If search points functions is set public virtual, developer can be implement a own search logic assuming the dataset is ordered,partially ordered or not ordered.

I think the best solution is 1) + 3).
1) is perfect for a lot of ordered case (In example dataset is database side ordered).
3) is perfect for more complex scenario.

Point 3) is already approved at http://feedback.telerik.com/Project/143/Feedback/Details/198360-chartview-make-the-getdatacontext-method-of-the-radchartbase-class-public-and-vi

Approved solution 3 at http://feedback.telerik.com/Project/143/Feedback/Details/198360-chartview-make-the-getdatacontext-method-of-the-radchartbase-class-public-and-vi