Hello Steven,

Thank you for your post.

I have been investigating into this functionality you are looking to achieve, and currently, I believe your best option would be to create a separate series based on the calculated values in the series that you are looking to create a trend line for. The XamDataChart currently does not have built-in functionality to create a trend line in a part of the chart, as the trend lines are currently designed as a calculated series that will span your data on a chart-wide scale. You can read a bit more about this, at the following blog post: http://ko.infragistics.com/community/blogs/kiril_matev/archive/2010/08/23/working-with-built-in-and-custom-logic-trendlines-in-the-xamdatachart.aspx.

If you would like to see a trend line extent option possibly added to the XamDataChart in the future, I would recommend suggesting a new product idea for it at http://ideas.infragistics.com. Submitting your idea will allow you to communicate directly with our product management team, track the progress of your idea at any time, see how many votes it got, read comments from other developers in the community, and see if someone from the product team has additional questions for you.

Remember when submitting your idea to explain the context in which a feature would be used and why it is needed as well as anything that would prevent you from accomplishing this today. You can even add screenshots to build a stronger case. Remember that for your suggestion to be successful, you need other members of the community to vote for it.  You can also link back to this thread for additional details.

Please let me know if you have any other questions or concerns on this matter.

Sincerely,
Andrew
Associate Developer
Infragistics Inc.
www.infragistics.com/support