如何将功能区按钮连接到Excel外接程序中定义的函数?

I'm using MSVS 2013 to create a C# MS Excel Add-In. In previous add-in paradigms, the ribbon class designer directly connected a ribbon button click event to function in the Add-In application class - now the ribbon functions are defined in the ribbon class, itself. What is the best way to access a function defined in the ThisAddIn class from the separate ribbon control class?I'm using MSVS 2013 to create a C# MS Excel Add