我想往以下的URL发送一个HTTP POST 如何发送 最好给出个源代码C#的

Question

using classes in System.Net, seeRetrieving HTTP content in .NET
http://www.west-wind.com/presentations/dotnetWebRequest/dotnetWebRequest.htm
        string strId = UserId_TextBox.Text;
string strName = Name_TextBox.Text; ASCIIEncoding encoding=new ASCIIEncoding();
string postData="userid="+strId;
postData += ("&username="+strName);
byte[]  data = encoding.GetBytes(postData); // Prepare web request...
HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create("http://localhost/MyIdentity/Default.aspx?x=2&y=2");
myRequest.Method = "POST";
myRequest.ContentType="application/x-www-form-urlencoded";
myRequest.ContentLength = data.Length;
Stream newStream=myRequest.GetRequestStream(); // Send the data.
newStream.Write(data,0,data.Length);
newStream.Close(); HttpWebResponse res = (HttpWebResponse) myRequest.GetResponse();
Encoding enc = System.Text.Encoding.GetEncoding("GB2312"); 
StreamReader sr = new StreamReader(res.GetResponseStream(),enc);
string sHtml = sr.ReadToEnd(); 
sr.Close(); res.Close();