[]
Gets the index number of this trendline within the collection of trendlines for the series.
The index identifies the trendline's position among similar objects in the same collection.
int Index { get; }
ReadOnly Property Index As Integer
worksheet.Range["A1:A4"].Value = new object[] { 10, 20, 30, 40 };
IShape shape = worksheet.Shapes.AddChart(ChartType.ColumnClustered, 20, 20, 360, 220);
shape.Chart.SeriesCollection.Add(worksheet.Range["A1:A4"], RowCol.Columns);
ITrendline trendline = shape.Chart.SeriesCollection[0].Trendlines.Add();
int index = trendline.Index;