Custom Format code behind 2013 Q1

[Dave]

I have done a custom format function in code behind


        public static string FormatYesNo(Int16 skill)
        {
            if (skill ==0)
                return "No";
            else
                return "Yes";
        }

But when i render the report i get this error shown in screen shot

[Squall]

The reporting engine can't find the user function because it works with bigger integers. Try to change the user function argument to Int64.

or just use this expression:
=IIF(skill = 0, "No", "Yes")

SN