如何发出HttpRequest对象

我这里定义了一个string为userinput（是一个URL）之后创建了一个HttpRequest对象
HttpRequest hrequest = new HttpRequest(null, userinput,null);

这里我不懂怎么把这个HttpRequest 对象发送出去。希望能得到各位大侠的帮助。

还有一个问题是我发送出去之后怎么接受他的HttpResponse对象。想在一个DiV中显示这个请求的页面信息（Response.ContentType=text类型的就显示他）。

string userinput = TextBoxUserInput.Text;
HttpRequest hrequest = new HttpRequest(null, userinput,null);
       ？？我如何发送出去同时得到他的Response


           string ct=Response.ContentType;
           if (ct.Substring(0, 4) == "text")
           {

               ？？显示在页面的一个DIV中
           } --------------------编程问答-------------------- HttpWebRequest通过post等提交到相关页面，获取执行的页面数据
private string HttpWebRequestLogin(string loginUrl, string postData, ref CookieContainer cookieContainer)
{
  byte[] bdata = Encoding.Default.GetBytes(postData);
  System.Net.HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(loginUrl);
  myRequest.Method = "POST";
  myRequest.ContentType = "application/x-www-form-urlencoded";
  myRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
  myRequest.Referer = loginUrl;
  myRequest.KeepAlive = true;
  myRequest.AllowAutoRedirect = true;
  if (cookieContainer == null)
  cookieContainer = new CookieContainer();
  myRequest.CookieContainer = cookieContainer;
  myRequest.ContentLength = bdata.Length;
  Stream newStream = myRequest.GetRequestStream();
  newStream.Write(l_data, 0, bdata.Length);
  newStream.Close();
  HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
  StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.GetEncoding("GB2312"));
  string content = reader.ReadToEnd();
  return content;
}

补充：.NET技术 ,  ASP.NET