一般我用于 需要获取网页返回的内容时调用 比较方便强大 支持自定义多参数

public static string HttpRequst(string RequstUrl, Dictionary h = null, string Method = "GET", bool IsTz = false)
        {
            if (h != null)
            {
                foreach (var item in h)
                {
                    RequstUrl += (RequstUrl.IndexOf("?") > -1 ? "&" : "?");
                    RequstUrl += item.Key + "=" + item.Value;
                }
            }
            string responseData = null;
            if (IsTz)
            {
                return RequstUrl;
            }
            HttpWebRequest webRequest = WebRequest.Create(RequstUrl) as HttpWebRequest;
            webRequest.Method = Method;
            webRequest.ServicePoint.Expect100Continue = false;
            webRequest.Timeout = 10000000;
            webRequest.ContentType = Content_Type;
            //webRequest.KeepAlive = true;
            StreamReader responseReader = null;
            try
            {
                responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream());
                responseData = responseReader.ReadToEnd();
            }
            catch
            {
            }
            finally
            {
                webRequest.GetResponse().GetResponseStream().Close();
                responseReader.Close();
                responseReader = null;
                webRequest = null;
            }
            return responseData;
        }

调用例子:

 Dictionary h = new Dictionary();
            h.Add("response_type", "code");
            h.Add("client_id", appid);
            h.Add("redirect_uri", "http://www.decadework.com/");
            h.Add("state", GetSha1(GetTimeStamp()));
            return HttpRequst("https://graph.qq.com/oauth2.0/authorize", h, "GET", true).Trim();

记录下 以后用 不需要到处找