c#.net内部异常捕获问题

public static void Download()
        {
            int count = 0;
            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://img.bimg.126.net/photo/c7bckFJxdJxSwQLIy76HTQ==/1755840904721658663.jpg");
                using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                {
                    byte[] buffer = new byte[64];
                    string temppath = "g:\\1755840904721658663.jpg";

                    using (System.IO.Stream downloadStream = response.GetResponseStream())
                    {
                        using (FileStream saveFileStream = new FileStream(temppath, FileMode.Create, FileAccess.Write, FileShare.None))
                        {
                            int readSize = 0;
                            while (true)
                            {
                                readSize = downloadStream.Read(buffer, 0, buffer.Length);
                                if (readSize <= 0) break;
                                saveFileStream.Write(buffer, 0, readSize);
                            }
                            Console.WriteLine("弹出");
                        }
                    }
                }
            }
            catch (System.Net.Sockets.SocketException ex)
            {
                Console.WriteLine("网络中断");
            }
            catch (Exception ex)
            {
                //throw ex;
                Console.WriteLine("异常类型：{0}", ex.GetType());
                Console.WriteLine("异常信息：{0}", ex.Message);
                Console.WriteLine("异常来源：{0}", ex.Source);
                Console.WriteLine("异常堆栈：{0}", ex.StackTrace);
                Console.WriteLine("内部异常：{0}", ex.InnerException);
            }
        }

异常类型：System.IO.IOException
异常信息：无法从传输连接中读取数据: 远程主机强迫关闭了一个现有的连接。。
内部异常：System.Net.Sockets.SocketException (0x80004005): 远程主机强迫关闭了一
个现有的连接。
  在 System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size,
 SocketFlags socketFlags)
  在 System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 s
ize)

IOException.InnerException是因为在读取Stream过程中，网络中断导致。

所以代码中应该加上一个Catch IOException的处理。

...
catch(IOException ex)
{
   if(IOException.InnerException is System.Net.Sockets.SocketException)
       Console.WriteLine("网络中断");
   else
       Console.WriteLine(ex.Message);
}
...