代码如下（基本上抄自msdn）：
WebRequest request = WebRequest.Create(url);
//request.Credentials = CredentialCache.DefaultCredentials;
request.ContentType = "application/x-www-form-urlencoded";
request.Method = "GET";
WebResponse response = request.GetResponse();
Console.WriteLine(((HttpWebResponse)response).StatusDescription);
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
Console.WriteLine(responseFromServer);
reader.Close();
response.Close();
return responseFromServer;
