如何用正则表达式得到sessionID的值

怎么用正则表达式得到sessionID的值
"http://regcheckcode.taobao.com/auction/checkcode?sessionID=9e2a04bb0081cc79906932e688641570&_ts=1318905551632"

[解决办法]

VB.NET code

Dim session_id as string = Regex.Match(yourStr,"(?<=sessionID=)[^&]+?(?=&|$)").Value