private void buttonLogin_Click(object sender, EventArgs e) { //new Views.AdminForm().Show(); string username = textBoxUsername.Text; string password = textBoxPass.Text; var resultA = AdminController.AuthenticateAdmin(username, password); var resultE = EmployeeController.AuthenticateEmployee(username, password); var resultC = CustomerController.AuthenticateCustomer(username, password); if (resultA != null) { new Views.AdminForm().Show(); } else if (resultE != null) { new Views.EmployeeForm().Show(); } else if (resultC != null) { new Views.CustomerForm().Show(); } else { MessageBox.Show("User not Valid"); } }