坑人的 try catch finally

一直以为这样可以关闭 fs, 其实不行

static void Main(string[] args)
                {
                                FileStream fs = null;
                                try
                                {
                                        fs = new FileStream(@"d:\data.txt", FileMode.Create);
                                        byte[] bytes = new UTF8Encoding().GetBytes("try");
                                        fs.Write(bytes, 0, bytes.Length);
                                        throw new Exception();//异常不作处理
                                }finally
                                {
                                        byte[] bytes = new UTF8Encoding().GetBytes(" finally");
                                        fs.Write(bytes, 0, bytes.Length);
                                        if (fs != null)
                                                fs.Close();
                                }
                }
  
要这样才能有效关闭 fs：

static void Main(string[] args)
                {
                        try
                        {
                                FileStream fs = null;
                                try
                                {
                                        fs = new FileStream(@"d:\data.txt", FileMode.Create);
                                        byte[] bytes = new UTF8Encoding().GetBytes("try");
                                        fs.Write(bytes, 0, bytes.Length);
                                        throw new Exception();//异常不作处理
                                }finally
                                {
                                        byte[] bytes = new UTF8Encoding().GetBytes(" finally");
                                        fs.Write(bytes, 0, bytes.Length);
                                        if (fs != null)
                                                fs.Close();
                                }
                        }
                        catch
                        {
                                throw;
                        }
                }