ip.IPv4Mask.GetHashCode()

https://read01.com/AJBM2N.html#.Wbe9PsgjFPY

http://blog.sanc.idv.tw/2012/01/c-equals.html

http://www.codedata.com.tw/java/guava-tutorial-4-object-common-methods/

http://apmtechtony.blogspot.tw/2017/09/c_12.html

http://charleslin74.pixnet.net/blog/post/454321301-%5bc%23%5d-%E6%A2%9D%E4%BB%B6%E5%BC%8F%E4%B8%AD%E5%B8%B8%E7%94%A8%E7%9A%84%26%E5%92%8C%26%26-%7c%E5%92%8C%7c%7c%E7%9A%84%E5%B7%AE%E7%95%B0

https://home.gamer.com.tw/creationDetail.php?sn=3450772

http://blog.darkthread.net/post-2016-08-09-gethashcode-issue.aspx

http://www.cnblogs.com/multiplesoftware/archive/2011/05/14/2046029.html

if (ip.IPv4Mask != null && ip.IPv4Mask.GetHashCode() == 0)

                        {

                            ethernetIPv6 = ip.Address.ToString();

                            //測試用

                            hashcode += ip.IPv4Mask.GetHashCode();

                            continue;

                        }

IPv4Mask: 0.0.0.0他的GetHashCode() == 0