C#带cookie Post和Get方式发送数据，保持cookie

在实际编程中，可能需要读取特定网页的信息，但很多网站需要用户登录后，才能够获取相关的页面内容，这就需要编程者先临时存储当前的cookie，
在C#中可以使用CookieContainer 对象来保存登录后的Cookie信息，这样，在每次发送数据的时候，附加上Cookie信息，就可以了。

#region 同步通过POST方式发送数据
/// <summary>
/// 通过POST方式发送数据
/// </summary>
/// <param name="Url">url</param>
/// <param name="postDataStr">Post数据</param>
/// <param name="cookie">Cookie容器</param>
/// <returns></returns>
public string SendDataByPost(string Url,string postDataStr,ref CookieContainer cookie)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
if (cookie.Count == 0)
{
request.CookieContainer = new CookieContainer();
cookie = request.CookieContainer;
}
else
{
request.CookieContainer = cookie;
}

request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = postDataStr.Length;
Stream myRequestStream = request.GetRequestStream();
StreamWriter myStreamWriter = new StreamWriter(myRequestStream, Encoding.GetEncoding("gb2312"));
myStreamWriter.Write(postDataStr);
myStreamWriter.Close();

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream myResponseStream = response.GetResponseStream();
StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
string retString= myStreamReader.ReadToEnd();
myStreamReader.Close();
myResponseStream.Close();

return retString;
}
#endregion

#region 同步通过GET方式发送数据
/// <summary>
/// 通过GET方式发送数据
/// </summary>
/// <param name="Url">url</param>
/// <param name="postDataStr">GET数据</param>
/// <param name="cookie">GET容器</param>
/// <returns></returns>
public string SendDataByGET(string Url, string postDataStr, ref CookieContainer cookie)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url +( postDataStr == "" ? "" : "?") + postDataStr);
if (cookie.Count == 0)
{
request.CookieContainer = new CookieContainer();
cookie = request.CookieContainer;
}
else
{
request.CookieContainer = cookie;
}

request.Method = "GET";
request.ContentType = "text/html;charset=UTF-8";

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream myResponseStream = response.GetResponseStream();
StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
string retString = myStreamReader.ReadToEnd();
myStreamReader.Close();
myResponseStream.Close();

return retString;
}
#endregion

操作代码

CookieContainer cc=new CookieContainer();
cc.Add(new System.Uri("http://www.baidu.com "), new Cookie("PHPSESSID", "xx"));
string content =  web.SendDataByGET("http://www.baidu.com/xx/yy.php","","gbk",ref cc);
MessageBox.Show(content);