The extension method is not visible


I am thinking to create some Extension method for the thing below.

So I plan to see


I created also the extancion method itself. But It is not appearing in place I need.

 @item.Roles.  Nothing what I need... :(

Any clue?


 public static class MyExtensions
        public static string ConvertToString(this ICollection<IdentityUserRole> identityUserRole)
            var result = string.Empty;

            return result;

You need to import the namespace containing your extension method using the @using directive.