C#访问url地址并返回数据

 public string getPostBackStream(string rUrl)
        {

            WebClient myWebClient = new WebClient();

            NameValueCollection myNameValueCollection = new NameValueCollection();
            myNameValueCollection.Add("title", "this is title");

            myNameValueCollection.Add("excerpt", "this is excerpt");
            byte[] responseArray = myWebClient.UploadValues(rUrl, "POST", myNameValueCollection);
            return Encoding.ASCII.GetString(responseArray);
        }