c# 取sessionid,该如何处理

c# 取sessionid
WebBrowser web = new WebBrowser();
web.Navigate(url);
上面两行打开网址后该怎样取sessionid。
（取cookie也行，里面也保存了sessionid）

（我对网页操作不在行哦）是winform

[解决办法]
CookieContainer myCookieContainer = new CookieContainer(); 
string cookieStr = webBrowser1.Document.Cookie; 
string[] cookstr = cookieStr.Split( '; '); 
foreach (string str in cookstr) 
{ 
 string[] cookieNameValue = str.Split('='); 
Cookie ck = new Cookie(cookieNameValue[0].Trim().ToString(), cookieNameValue[1].Trim().ToString()); 
ck.Domain = "";
myCookieContainer.Add(ck); 
}