StreamWriter store = new StreamWriter("f1.txt");
                foreach (string i in listBox1.Items)
                {
                    store.WriteLine(i);
                }     
            store.Flush();
            store.Close();
            StreamWriter store2 = new StreamWriter("f2.txt");
                foreach (string i in listBox2.Items)
                {
                    store2.WriteLine(i);
                }
            store2.Flush();
            store2.Close();