GemBox Retrieving Calculated Values From a Spreadsheet or Flexcel

Question

According to their docs: GemBox.Spreadsheet can read and write formulas, but can not calculate formula results. When you open a XLS file in MS Excel, formula results will be cal

Answer 1

What is your actual question?

Cells have two properties: values and formulas. What you're seeing is value beeing recalculated by Excel on the fly. Gembox, as you said, doesn't recalculate the values.

If you need formula evaluation, look for another library, for example Apache POI.

Answer 2

EDIT 28-09-2016:
We have released a new version of GemBox.Spreadsheet (version 4.1) in which we implemented a support for cell formula calculation, see the version history page.
Also, you can find the calculation example here.

ORIGINAL ANSWER
GemBox.Spreadsheet currently supports only values that are calculated by the Excel (so if file is saved by the MS Excel, we can read formula values). GemBox.Spreadsheet does not have its own calculation engine.

To read formula values in XLS format use ExcelFile.LoadXls overload that accepts XlsOptions enumeration and use XlsOptions.PreserveWorksheetRecords or XlsOptions.PreserveAll.

To read formula values in XLSX format use ExcelFile.LoadXlsx method with XlsxOptions enumeration values XlsxOptions.PreserveKeepOpen or XlsxOptions.PreserveMakeCopy.