Some code

        static void Main(string[] args)
        {
            //Operaciones de Strings
            string a = "String1";
            string b = "String2";

            Console.WriteLine(String.Concat(a,b)); //concatenar
            Console.WriteLine(a.Insert(2,b)); //Insertar
            string c = b.Remove(3, 6); //Remover
            Console.WriteLine(c);
            string d = a.Substring(1, 5); //Formar SubCadena
            Console.WriteLine(d);
            string e = a.Replace("String", "Cadena"); //Reemplazar 
            Console.WriteLine(e);
            String f = string.Copy(e); //Copiar

            //Iterar string
            foreach (char x in a)
            {
                Console.WriteLine(x);
            }

            string g = "Este es mi string al 6/5/11";
            char[] some = { ' ' };
            List<string> G = new List<string>();
            G.AddRange(g.Split(some));

            foreach (string a1 in G)
            { Console.WriteLine(a1); }

            string h = Microsoft.VisualBasic.Strings.StrReverse(a);
            Console.WriteLine(h);

            bool x1 = Convert.ToBoolean(string.Compare(a, b, true));

            //Convertir Strings en arrays de bytes
            Byte[] s1 = Encoding.UTF8.GetBytes(a);
            String s1_1 = Encoding.UTF8.GetString(s1);

            //Buscar palabra con regular expressions
            string cad1 = "ad";
            string cad2 = "ad-sense, ads";

            System.Text.RegularExpressions.Regex rex = new System.Text.RegularExpressions.Regex(cad1);
            int count = rex.Matches(cad2).Count;
            Console.WriteLine(cad1 + " occurs " + count + " times");

        }