Very simple 64bit C# implementation of an Excel RTD Server for Excel 64bit have a look at http://blog.alignment-systems.com/2014/10/excel-rtd-server-implementation-in.html and http://blog.alignment-systems.com/2014/05/excel-rtd-server-implementation-in.html for details of what this does...
YuriWerewolf/ExcelRTDSimple
Very simple 64bit C# implementation of an Excel RTD Server for Excel 64bit
C#