C#之拋異常

using System;

namespace Demo
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                BLLLayer();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.StackTrace);
                Console.WriteLine("===================================");
                Console.WriteLine(ex.ToString());
            }
            Console.ReadKey();
        }

        static void BLLLayer()
        {
            try
            {
                DAOLayer();
            }
            catch (Exception ex)
            {
                //throw;  //可溯源到DAO
                //throw ex;  //可溯源終點就是這裏
                //throw new Exception("BLL層異常");       //可溯源終點就是這裏，拋出新的異常，吞併原來的異常
                //throw new Exception("BLL層異常", ex); //可溯源終點就是這裏，拋出新的異常，帶着原來的異常
            }
        }

        static void DAOLayer()
        {
            try
            {
                throw new Exception("DAO層異常");
            }
            catch
            {
                throw;
            }
        }
    }
}