在后端C#中 call web api 关联lookup 和 GUID

                var weburi = resourceUrl + "api/data/v9.1/accounts";
                AuthenticationContext authContext = new AuthenticationContext("https://login.windows.net/common", false);
                AuthenticationResult result = authContext.AcquireToken(resourceUrl, clientId, new UserCredential(account, password));
                HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(weburi);

                req.Method = "post";
                req.Accept = "application/json";
                req.ContentType = "application/json; charset=utf-8";
                req.Headers.Add("OData-MaxVersion", "4.0");
                req.Headers.Add("OData-Version", "4.0");
                req.Headers.Add("If-Match","*");
                req.Headers.Set("Authorization", "Bearer " + result.AccessToken);
                ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;

                var newSurveyResult = new JObject();
                newSurveyResult.Add("booleanvalue", true);
                newSurveyResult.Add("stringvalue", "Hello World!");
                var interviewee = "/sfdhl_0365users(fa903a51-3d2a-48d5-bbbb-c225f1cf2482)";
                newSurveyResult.Add("o365userinterviewee@odata.bind", interviewee);
                newSurveyResult.Add("businessgroup", "fa903a51-3d2a-48d5-bbbb-c225f1cf2482");
                byte[] data = Encoding.UTF8.GetBytes(newSurveyResult.ToString());
                Stream newStream = req.GetRequestStream();
                newStream.Write(data, 0, data.Length);
                newStream.Close();
                using (HttpWebResponse res = (HttpWebResponse)req.GetResponse())
                {
                    //StreamReader read = new StreamReader(res.GetResponseStream());
                    string head = res.Headers.ToString();
                }