IChartTrendLine Order Property

<para>//Create worksheet</para><para>Workbook workbook = new Workbook();</para><para>workbook.LoadFromFile("Sample.xlsx");</para><para>Worksheet worksheet = workbook.Worksheets[0];</para><para>//Create chart</para><para>Chart chart = worksheet.Charts.Add(ExcelChartType.ColumnClustered);</para><para>//Add serie and set serie Y and X Values</para><para>IChartSerie serie = chart.Series.Add();</para><para>serie.Values = worksheet.Range["A2:C2"];</para><para>serie.CategoryLabels = worksheet.Range["A1:C1"];</para><para>//Get chart trendlines collection and Add trendline</para><para>IChartTrendLines trendLines = serie.TrendLines;</para><para>IChartTrendLine trendline = trendLines.Add();</para><para>//Set trendline type</para><para>trendline.Type = TrendLineType.Polynomial;</para><para>//Set trendline order</para><para>trendline.Order = 6;</para><para>//Save to file</para><para>workbook.SaveToFile("Chart.xlsx");</para>