学步园

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

namespace test_try_catch_finally
{
    class Program
    {
        private static bool OpenFile()
        {
            bool ret = false;
            try
            {
                try
                {
                    File.Open(@"C:\windows\notepad.x", FileMode.Open);
                    ret = true;
                }
                catch (Exception ex)
                {
                    throw ex;
                    Console.WriteLine("Exception：{0}", ex.Message);
                    ret = true;
                }
                finally
                {
                    Console.WriteLine("Finally");
                    ret = true;
                }
                Console.WriteLine("ret:{0}", ret.ToString());
                return ret;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception：{0}", ex.Message);
                ret = false;
            }
            Console.WriteLine("ret:{0}", ret.ToString());
            return ret;
        }

        static void Main(string[] args)
        {
            Console.WriteLine("RET：{0}", OpenFile());
            Console.ReadKey();
        }
    }
}

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以上代码测试结果,觉得它的执行顺序很值得纪录:

首先在底层的顺序是, try中File.Open(@"C:\windows\notepad.x", FileMode.Open);报错后,跳进底层catch块执行完throw后,接着马上跳进底层finally块执行完,接着就跳进上层的catch块了,执行完上层catch后,最后去执行完上层catch块后面的Console.WriteLine("ret:{0}", ret.ToString());  return ret;

--------------------------致此,函数的调用得以完成.

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

namespace test_try_catch_finally
{
    class Program
    {
        private static bool OpenFile()
        {
            bool ret = false;
            try
            {
                try
                {
                    File.Open(@"C:\windows\notepad.x", FileMode.Open);
                    ret = true;
                }
                catch (Exception ex)
                {
                    return false;
                    throw ex;
                    Console.WriteLine("Exception：{0}", ex.Message);
                    ret = true;
                }
                finally
                {
                    Console.WriteLine("Finally");
                    ret = true;
                }
                Console.WriteLine("ret:{0}", ret.ToString());
                return ret;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception：{0}", ex.Message);
                ret = false;
            }
            Console.WriteLine("ret:{0}", ret.ToString());
            return ret;
        }

        static void Main(string[] args)
        {
            Console.WriteLine("RET：{0}", OpenFile());
            Console.ReadKey();
        }
    }
}

下面的因为低层的catch中有return false;在throw ex;之前,所以在catch中走完return false;之后,直接跳进底层finally块执行完,函数就调用结束了...