private void button1_Click(object sender, EventArgs e)
        {
            string abc = "qwertyuiopasdfghjklzxcvbnm!@#$%^&*()123456789QWERTYUIOPASDFGHJKLZXCVBNM";

            string result = "";

            Random rnd = new Random();
            int lng = abc.Length;
            for (int i = 0; i < 10; i++)
                result += abc[rnd.Next(lng)];
            textBox2.Text = result;
        }