private void loginBtn_Click(object sender, EventArgs e)
        {
            if (usernameTxt.Text == "")
            {
                usernameErrorLabel.Visible = true;
            }
            else
            {
                usernameErrorLabel.Visible = false;
            }
            if (passwordtxt.Text == "")
            {
                passwordErrorLabel.Visible = true;
            }
            else
            {
                passwordErrorLabel.Visible = false;
            }

            if (usernameErrorLabel.Visible || passwordErrorLabel.Visible)
            {
                MainClass.ShowMSG("Fields with * are mandatory.", "Error", "Error");
            }
            else
            {
                if (mai.getStaffLogin(usernameTxt.Text, passwordtxt.Text))
                {
                    if (MainClass.STAFFROLE == "Faculty")
                    {
                        FacultyDB hs = new FacultyDB();
                        MainClass.showWindow(hs, this, MDI.ActiveForm);
                        MDI.mdiobj.logoutToolStripMenuItem.Enabled = true;
                        this.Close();
                    }
                    else if (MainClass.STAFFROLE == "Admin")
                    {
                        HomeScreen hs = new HomeScreen();
                        MainClass.showWindow(hs, this, MDI.ActiveForm);
                        MDI.mdiobj.logoutToolStripMenuItem.Enabled = true;
                        this.Close();
                    }
                }
                else
                {
                    MainClass.ShowMSG("Invalid login details.", "Error", "Error");
                }
            }
        }