private void button1_Click(object sender, EventArgs e)
        {
            string username = textBox2.Text;
            string password = textBox1.Text;
            int    id       = DBMng.validateHSP(username, password);

            if (id != 0)
            {
                this.Hide();
                HSPinfoGUI info = new HSPinfoGUI(id);
                info.ShowDialog();
            }
            else
            {
                label4.Visible = true;
            }
        }