Assembly: Microsoft.Office.Interop.Excel (in microsoft.office.interop.excel.dll)
The Trendline object is a member of the Trendlines collection. The Trendlines collection contains all the Trendline objects for a single series.
Use Trendlines(index), where index is the trendline index number, to return a single Trendline object.
The index number denotes the order in which the trendlines were added to the series. Trendlines(1) is the first trendline added to the series, and Trendlines(Trendlines.Count) is the last one added.