private void Button_add_Click(object sender, EventArgs e) { if (textBox_permission_level.Text.Trim().Equals("")) { MessageBox.Show("Please do not leave the textbox empty."); return; } if (controller.HasPermission(Int32.Parse(textBox_permission_level.Text))) { MessageBox.Show("Permission " + textBox_permission_level.Text + " already exists."); return; } controller.AddPermission(Int32.Parse(textBox_permission_level.Text)); PermissionAdded(); }