如何确定数组中的对象数

Once again I cannot find a solution myself (I have tried using Array.IndexOf(db, accnum) with a pos > -1 return boolean, but have reverted to this loop after I couldn't make it work). So, I thought using db.Length would leave 'a' at the length of all the non-null elements in the array, however it seems to count the whole array, meaning that when the loop reaches a null element it causes an error. Is there a way to halt the loop count when it runs out of objects in the array? Once again I cannot find a solution myself (I h