Exception处理机制

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            //Level1
            try
            {               
                //Level2
                try
                {
                    
                    //Level3
                    try
                    {
                        //throw new ExceptionA("Exception in Level3");
                        //throw new ExceptionB("Exception in Level3");
                    }
                    catch (ExceptionA)
                    {
                        Console.WriteLine("Level3中处理Exception");
                    }
                    finally
                    {
                        Console.WriteLine("Level3中的finally语句块");
                    }
                    throw new ExceptionC("Exception in Level2");
                }
                catch (ExceptionB)
                {
                    Console.WriteLine("Level2中处理Exception");
                }
                finally
                {
                    Console.WriteLine("Level2中的finally语句块");
                }
                //throw new Exception("Exception in Level1");
            }
            catch (ExceptionC)
            {
                Console.WriteLine("Level1中处理ExceptionC");
            }
            catch (Exception)
            {
                Console.WriteLine("Level1中处理Exception");
            }
            finally
            {
                Console.WriteLine("Level1中的finally语句块");
            }


            Console.ReadKey();

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
    class ExceptionA : Exception
    {
        public ExceptionA(string mess):base(mess)
        {
        }
    }
}

首先在同级查找是否存在兼容的异常，如果没有，则一级一级往上