How to create chart/graph in excel sheet OpenXML 2.0 C#

To get an existing worksheet to edit use this code to get the part:

        public static WorksheetPart GetWorksheetPart(WorkbookPart workbookPart, string sheetName)
        {
            string relId = workbookPart.Workbook.Descendants<Sheet>()
                                 .Where(s => sheetName.Equals(s.Name))
                                 .First()
                                 .Id;

            return (WorksheetPart)workbookPart.GetPartById(relId);
        }

Just make sure that the sheetname exists you are searching for or you will get some exceptions. Then use the reference to that worksheetpart to perform any edits your want and at the end just call worksheetPart.Worksheet.Save();

EDIT

The SheetProtection element needs to be inserted after the SheetData element. Try this line when appending: worksheetPart.Worksheet.Descendants<SheetData>().First().InsertAfterSelf(sheetProtection1);

By default std::map uses std::less<std::reference_wrapper<const Object>> as Compare, but std::reference_wrapper<T> doesn't forward operator<() to the underlying type T.

The simplest and concisest option to solve your problem is to define std::less<const Object> (or std::greater<const Object>) in the map definition like this:

std::map<std::reference_wrapper<const Object>, int, std::less<const Object>> table;

It will work correctly and as expected due to implicit conversion of std::reference_wrapper to T& and implicit constructor of std::reference_wrapper.

Example.