This class is a tool for converting AR TextBox's OutputFormat and Value to Excel NumberFormat and Value. AR TextBox's OutputFormat is based on .NET Framework Formatting. See http://msdn.microsoft.com/en-us/library/fbxft59x(v=vs.80) In addition, AR OutputFormat also supports the forth section and _(undersorce). For Excel NumberFormat, see http://www.brainbell.com/tutorials/ms-office/excel/Create_Custom_Number_Formats.htm