sL = new List<System.String>(sA); System.String[] nextString = sL.ToArray();

    class Program
    {
        static void Main(string[] args)
        {
            System.String[] sA = { "str", "string1", "sting2", "abc" };
            List<System.String> sL = new List<System.String>();
            for (System.Int32 i = 0; i < sA.Length; i++)
            {
                Console.WriteLine("sA[{0}]={1}", i, sA[i]);
            }
            //
            sL = new List<System.String>(sA);
            sL.Add("Hello!");
            foreach (System.String s in sL)
            {
                Console.WriteLine(s);
            }
            //
            System.String[] nextString = sL.ToArray();
            Console.WriteLine("The Length of nextString is {0}", nextString.Length);
            Console.Read();
            /*
            sA[0]=str
            sA[1]=string1
            sA[2]=sting2
            sA[3]=abc
             * 
            str
            string1
            sting2
            abc
            Hello!
             * 
            The Length of nextString is 5
            */
        }
    }