Converting Array or List of data to String => made easy! (C#, MVC3, LINQ)

string.Join(",", Array.ConvertAll(cities, c => c.Name));

A Linq solution that works under .NET 3.5 is:

string.Join(",", cities.Select(c => c.Name).ToArray());

This is less efficient than ConvertAll because it is iterating through the array via the IEnumerable interface.