public static void Run()
{
//Load sample workbook
Workbook wb = new Workbook(sourceDir + "sampleGroupPivotFieldsInPivotTable.xlsx");
//Access the second worksheet
Worksheet ws = wb.Worksheets[1];
//Access the pivot table
PivotTable pt = ws.PivotTables[0];
//Specify the start and end date time
DateTime dtStart = new DateTime(2008, 1, 1); //1-Jan-2018
DateTime dtEnd = new DateTime(2008, 9, 5); //5-Sep-2018
//Specify the group type list, we want to group by months and quarters
ArrayList groupTypeList = new ArrayList();
groupTypeList.Add(PivotGroupByType.Months);
groupTypeList.Add(PivotGroupByType.Quarters);
//Apply the grouping on first pivot field
pt.SetManualGroupField(0, dtStart, dtEnd, groupTypeList, 1);
//Refresh and calculate pivot table
pt.RefreshDataFlag = true;
pt.RefreshData();
pt.CalculateData();
pt.RefreshDataFlag = false;
//Save the output Excel file
wb.Save(outputDir + "outputGroupPivotFieldsInPivotTable.xlsx");
Console.WriteLine("GroupPivotFieldsInPivotTable executed successfully.");
}