Best method to call c# code from within Excel or Excel VBA

Can anyone tell me 开发者_JAVA技巧the best method for calling c# from within Excel.

I saw a post somewhere that said the later .NET had good ways to do this - but nothing was specified.

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Not sure if @amit_g's link is what you mean, but the post may also have said that for Excel 2007 and up you can create an add-in in Visual Studio.