// them bill
public object insertBill(string date, int totalprice)
{
string query = "insert into Bill(Date, TotalPrice) values (@date, @totalprice); select SCOPE_IDENTITY() ";
object[] value = new object[] { date, totalprice };
DBConnect db = new DBConnect();
//_id = (int)(db.ExecuteScalar(query, value));
_id = Int32.Parse(db.ExecuteScalar(query, value).ToString());
return(_id);
//return (db.ExecuteNonQuery(query, value) > 0);
}