C#集合

http://www.cnblogs.com/kissdodog/archive/2013/01/29/2882195.html
http://www.cnblogs.com/jesse2013/p/CollectionsInCSharp.html http://www.cnblogs.com/Capricornus/archive/2010/08/17/1801596.html http://www.cnblogs.com/zacy110/p/5271858.html http://www.cnblogs.com/yangrouchuan/p/5155557.html http://www.cnblogs.com/teroy/p/3134666.html http://www.cnblogs.com/louby/p/5286493.html http://www.cnblogs.com/woxpp/p/3935557.html http://www.cnblogs.com/fanyong/archive/2011/09/15/2177877.html http://blog.knowsky.com/270408.htm http://www.kuqin.com/shuoit/20150331/345474.html http://www.cnblogs.com/ringnet/archive/2006/09/16/505936.html
Hashtable转换成Enmuerator：

Hashtable hOnline = (Hashtable)Application["Online"];
if (hOnline!= null)
{
IDictionaryEnumerator idE = hOnline.GetEnumerator();
string strKey = "";
while (idE.MoveNext())
{
if (idE.Value!= null && idE.Value.ToString().Equals(UserID))
{ //already login
strKey = idE.Key.ToString();
hOnline[strKey] = "XXXXXX";
break;
}
}
}
else
{
hOnline = new Hashtable();
}