public string Post(string url, string content)
{
string contentType = "application/json"; //Content-Type
try
{
var client = new RestClient(url);
var request = new RestRequest(Method.POST);
request.Timeout = 10000;
request.AddParameter(contentType, content, ParameterType.RequestBody);

IRestResponse response = client.Execute(request);
return response.Content; //返回的结果
}
catch (Exception ex)
{
return "连接服务器出错：\r\n" + ex.Message;
}
}

public class RestClientManager

    {

        public JObject Post(string baseUrl, string url, JObject sendData)

        {

            return Post(baseUrl, url, sendData, string.Empty);

        }

        public JObject Post(string baseUrl, string url, JObject sendData, string token)

        {

            RestClient client = new RestClient(baseUrl);

            var request = new RestRequest(url, Method.POST);

            var contenType = "application/json";

            request.AddHeader("Accept", contenType);

            if (!string.IsNullOrWhiteSpace(token))

            {

                request.AddHeader("token", token);

            }

            if (sendData == null)

            {

                sendData = new JObject();

            }

            request.AddParameter(contenType, sendData, ParameterType.RequestBody);

            var response = client.Execute(request);

            if (string.IsNullOrWhiteSpace(response.Content))

            {

                return null;

            }

            return JObject.Parse(response.Content);

        }

        public JObject Get(string baseUrl, string url, JObject sendData)

        {

            return Get(baseUrl, url, sendData, string.Empty);

        }

        public JObject Get(string baseUrl, string url, JObject sendData, string token)

        {

            string parames = string.Empty;

            if (sendData != null)

            {

                StringBuilder datas = new StringBuilder();

                foreach (var item in sendData)

                {

                    datas.AppendFormat("{0}={1}", item.Key, item.Value);

                }

                parames = string.Format("?{0}", string.Join("&", datas));

            }

            var client = new RestClient(string.Format("{0}{1}{2}", baseUrl, url, parames));

            var request = new RestRequest(Method.GET);

            var response = client.Execute(request);

            return JObject.Parse(response.Content);

        }

    }

　　　　　　　string baseUrl = "https://api.weixin.qq.com";

            string urlToken = @"/sns/oauth2/access_token";

            JObject paras = new JObject

            {

                ["appid"] = "",

                ["secret"] = "",

                ["code"] = "",

                ["grant_type"] = "authorization_code"

            };

            JObject objToken = new RestClientManager().Get(baseUrl, urlToken, paras);

　　　　　　　if (objToken["errcode"] == null)

            {

                string access_token = objToken["access_token"].Value<string>();

                string openid = objToken["openid"].Value<string>();

　　　　　　　}