private void Button_Click(object sender, RoutedEventArgs e)
        {
            String username = textbox1.Text.ToString();
            String password = textbox2.Text.ToString();

            if (ClientService.login(username, password) == false)
            {
                MessageBox.Show("Nume sau parola gresita");
            }
            else
            {
                //Chat win2 = new Chat(ClientService.getClient());
                Chat win2 = new Chat(communication, username);

                win2.Show();
                this.Close();
            }
        }