C# attributes not recognised

Question

This must be a silly question: I am learning C# here, and I am trying to build a dll which has an iniFile class. the code is direct copy from Code source is here

This project fails to build with error "the type or namespace 'DllImportAttribute' could not be found (are you missing a using directive or an assembly reference?)". The error flags at

[DllImport("kernel32")]

If I comment the attributes out, the build goes well. It must be setting somewhere to resolve this. Any suggestion is welcome..thx

--update-- thanks!

Answer 1

Ensure using System.Runtime.InteropServices; is at the top of your file.

Answer 2

Ensure you have a using for:

System.Runtime.InteropServices