ESharper is an Excel add-in that lets you write user defined functions and commands using C# interactively in a live Excel session.
V1.8.0 lets you edit function and command code with IntelliSense and syntax highlighting in Visual Studio 2019:
If you add the [ExcelDna.Integration.ExcelCommand()] attribute to a method in the functions task pane, it will be registered as a command that you can add to the Ribbon:
https://tabsstudio.com/
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