Excel.Workbook workBook = appXLS.Workbooks.Open(fullPathWaveLength);

Excel.Worksheet workSheet = workBook.Worksheets[1];

Excel.ChartObjects chartObjects = workSheet.ChartObjects();

Excel.ChartObject chartObject1 = workSheet.ChartObjects(1);

Excel.ChartObject chartObject2 = workSheet.ChartObjects(2);

GetTrendLine(chartObject1);

GetTrendLine(chartObject2);

void GetTrendLine(Excel.ChartObject chartObject)

{

Excel.Chart chart = chartObject.Chart;

Excel.Series series = (Excel.Series)chart.SeriesCollection(1);

Excel.Trendline trendline = series.Trendlines(1);

Excel.DataLabel dataLabel = trendline.DataLabel;

Console.WriteLine(dataLabel.Text);

}

These are very simple code.

But I don't know what make the error.

I ordered both charts to be read at the same time, but as you can see, there was only one result.

I want to get even a little hint.