ESharper add-in for Excel 2013/2016 lets you write user defined functions and commands using C#:
As you change C# code and click Register in the ESharper custom task pane, the updated functions immediately become available in the current running Excel instance and the active sheet is automatically recalculated.
You can write as many UDF functions for Excel as you want, just declare them public and static in the code.
You can use C# 4.0 language features when .NET 4 is installed and C# 5.0 features when .NET 4.5 is installed.
You can create global functions available for any workbook on your computer and workbook functions stored in a .xlsx file. A command created with ESharper lets you automate Excel operations.
It’s my new product. Please send any questions or suggestions to SergeyVlasov@vlasovstudio.com
https://tabsstudio.com/
Making Visual Studio perfect 