通过HttpWebRequest获取网页内容并保持session，最主要的就是存储cookie。这里使用了一个静态变量m_Cookie用来存储cookie的内容。第二次请求网页的时候把cookie传送过去，这样就可以保持session。

1. public partial class RequestPage : System.Web.UI.Page  
2.     {  
3.         private static CookieContainer m_Cookie = new CookieContainer();  
4.         private string m_Url = "http://localhost/HttpRequestTest/SessionPage.aspx";  
5.         protected void Page_Load(object sender, EventArgs e)  
6.         {  
7.             string content = GetPageContent();  
8.               
9.             Label1.Text = content;  
10.         }  
11.   
12.           
13.           
14.           
15.           
16.         private string GetPageContent()  
17.         {  
18.             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(m_Url);  
19.             request.CookieContainer = m_Cookie;  
20.             HttpWebResponse response = (HttpWebResponse)request.GetResponse();  
21.             string cookieheader = request.CookieContainer.GetCookieHeader(new Uri(m_Url));  
22.             m_Cookie.SetCookies(new Uri(m_Url), cookieheader);  
23.   
24.             Stream stream = response.GetResponseStream();  
25.             StreamReader reader = new StreamReader(stream);  
26.             string result = reader.ReadToEnd();  
27.   
28.             stream.Close();  
29.             reader.Close();  
30.             response.Close();  
31.   
32.             return result;  
33.         }  
34.   
35.           
36.           
37.           
38.           
39.           
40.         public string GetPageContent(string url)  
41.         {  
42.             StringBuilder result = new StringBuilder("");  
43.             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); ;  
44.             HttpWebResponse reponse = null;  
45.             try  
46.             {  
47.                 request.CookieContainer = m_Cookie;  
48.                 reponse = (HttpWebResponse)request.GetResponse();  
49.                 m_Cookie = request.CookieContainer;  
50.                 Stream rspStream = reponse.GetResponseStream();  
51.                 StreamReader sr = new StreamReader(rspStream, System.Text.Encoding.Default);  
52.   
53.                   
54.                 Char[] read = new Char[256];  
55.                 int count = sr.Read(read, 0, 256);  
56.                 while (count > 0)  
57.                 {  
58.                     result.Append(read, 0, count);  
59.                     count = sr.Read(read, 0, 256);  
60.                 }  
61.             }  
62.             catch (Exception e)  
63.             {  
64.                 result.Append(e.Message);  
65.             }  
66.             finally  
67.             {  
68.                 if (reponse != null)  
69.                 {  
70.                     reponse.Close();  
71.                 }  
72.             }  
73.             return result.ToString();  
74.         }  
75.     }