private void login() { string username = usnTxtBox.Text; string password = passTxtBox.Text; query = "select * from LoginInfo where Username = N'" + username + "' and Password = N'" + password + "' "; config.GetSingleResult(query); config.GetRole(query); if (config.dt.Rows.Count > 0) { if (config.role == "manager") { MainPage_Manager a = new MainPage_Manager(usnTxtBox.Text); this.Hide(); a.ShowDialog(); this.Show(); } else if (config.role == "scientist") { MainPage_Scientist b = new MainPage_Scientist(usnTxtBox.Text); this.Hide(); b.ShowDialog(); this.Show(); } } else { MessageBox.Show("Account does not exist! Please contact administrator.", "", MessageBoxButtons.OK, MessageBoxIcon.Error); } }