验证码
ASP.NET中怎样添加验证码，最好是控件形式的，求大神给力，新手
[解决办法]
http://bbs.51cto.com/thread-555596-1.html
http://index.cnblogs.com/archive/2004/10/20/54692.aspx
http://www.cnblogs.com/liudao/archive/2007/04/29/732065.html
http://blog.csdn.net/zhangyj_315/article/details/2688752
http://www.enet.com.cn/article/2004/0212/A20040212285343.shtml
