{ 
        "token_type": "Bearer", 
        "expires_in": "3600", 
        "ext_expires_in": "3600", 
        "expires_on": "1562587331", 
        "not_before": "1562583431", 
        "resource": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
 
        "access_token": "xxxxxxxxxxxxxxxxx...xxxxxxxxxxxxxx" 
    }
  
  
  
   
  
  private object
  GetAccessToken()
  
          {
  
              //throw new NotImplementedException();
  
              string uri = "https://login.microsoftonline.com/ec8933c6-cfb2-4dd9-bfc9-621cde1dea8f/oauth2/token";
  
              var client_id = ConfigurationManager.AppSettings["client_id"];
  
              var client_secret = ConfigurationManager.AppSettings["client_secret"];
  
              var resource = ConfigurationManager.AppSettings["resource"];
  
   
  
              string body = "client_id="
  + client_id + "&client_secret=" + client_secret + "&grant_type=client_credentials&resource="
  + resource;
  
              AccessTokens tokens;
  
              var request = (HttpWebRequest)WebRequest.Create(uri);
  
              request.Method = "POST";
  
              request.Accept = "application/json";
  
              request.ContentType = "application/x-www-form-urlencoded";
  
   
  
              request.ContentLength = body.Length;
  
   
  
              using (Stream
  requestStream = request.GetRequestStream())
  
              {
  
                  StreamWriter writer = new
  StreamWriter(requestStream);
  
                  writer.Write(body);
  
                  writer.Close();
  
              }
  
   
  
              var response = (HttpWebResponse)request.GetResponse();
  
   
  
              using (Stream
  responseStream = response.GetResponseStream())
  
              {
  
                  var reader = new
  StreamReader(responseStream);
  
                  string json = reader.ReadToEnd();
  
                  reader.Close();
  
                  tokens = JsonConvert.DeserializeObject(json,
  typeof(AccessTokens))
  as AccessTokens;
  
              }
  
   
  
              return tokens.AccessToken;
          }