Can we add UDF in excel template through visual studio

I have a excel template(.xlt), and I want to do custom validation for this can I use macro, I am doing coding in c#, When I pressF11 in visual studio it opens the macro editor of visual studio but not of excel...Is there any way to add macro or UDF so that I can use User Defined Function in custom validation of 开发者_Go百科excel.

If you want to write the UDF in VBA (which sounds like the simplest solution) then open the .xlt in Excel, press F11 to get the Excel VBE and add the VBA UDF to a standard module, then save the file as an .xlt typ