using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        string delimiter = ",";

        List<string> items = new List<string>() { "foo", "boo", "john", "doe" };

        Console.WriteLine(items.Aggregate((i, j) => i+ delimiter + "'" + j + "'" ));

        Console.WriteLine(string.Join(','items))

    }

}