public class CrmAuth
     {
         ///<summary>
         /// Token
         /// </summary>
         public string access_token { get; set; }

         ///<summary>
         /// 类型
         /// </summary>
         public string token_type { get; set; }

         ///<summary>
         /// 有效期 秒
         /// </summary>
         public int expires_in { get; set; }

         ///<summary>
         /// refresh_Token 用于刷新Token
         /// </summary>
         public string refresh_token { get; set; }

         /// <summary>
         /// 请求Token
         /// </summary>
         /// <param name="adfsUri">ADFS地址</param>
         /// <param name="resource">CRM地址</param>
         /// <param name="clientId">客户端ID</param>
         /// <param name="redirectUri">跳转地址</param>
         /// <param name="userName">用户名</param>
         /// <param name="password">密码</param>
         /// <returns></returns>
         public static CrmAuth AcquireToken(string adfsUri, string resource, string clientId, string redirectUri, string userName, string password)
         {
             VerifyParams(adfsUri, resource, clientId, redirectUri, userName, password);

             var url = BuildCodeUrl(adfsUri, resource, clientId, redirectUri);

             var tokenUrl = BuildTokenUrl(adfsUri);

             var list = BuildCodeParams(userName, password);

             //包含上下文的 用WebRequest也可以
             using (var handler = new WebRequestHandler { AllowAutoRedirect = false })
             {
                 using (var httpClient = new HttpClient(handler))
                 {
                     //第1次请求
                     using (var response = httpClient.PostAsync(url, new FormUrlEncodedContent(list)).Result)
                     {
                         // 第2次请求 httpClient 还要用之前的 包含了第一次返回的Cookies
                         using (var response2 = httpClient.GetAsync(response.Headers.Location).Result)
                         {
                             // 获取返回的Code
                             var query = response2.Headers.Location.Query;
                             var col = Utils.GetQueryString(query);
                             var code = col["code"];
                             if (string.IsNullOrWhiteSpace(code))
                             {
                                 throw new Exception(query);
                             }
                             // 第3次请求 请求Token
                             var tokenParams = BuildTokenParams(clientId, code, resource, redirectUri);
                             using (var response3 = httpClient.PostAsync(tokenUrl, new FormUrlEncodedContent(tokenParams)).Result)
                             {
                                 var json = response3.Content.ReadAsStringAsync().Result;
                                 var auth = JsonConvert.DeserializeObject<CrmAuth>(json);
                                 if (auth == null)
                                     throw new Exception(json);
                                 return auth;
                             }

                         }
                     }
                 }
             }
         }

         /// <summary>
         /// 刷新Token
         /// </summary>
         /// <param name="adfsUri"></param>
         /// <param name="refresh_token"></param>
         /// <returns></returns>
         public static CrmAuth CrmRefreshToken(string adfsUri, string refresh_token)
         {
             var tokenUrl = BuildTokenUrl(adfsUri);
             using (var httpClient = new HttpClient())
             {
                 // 请求 请求Token
                 var tokenParams = BuildRefreshTokenParams(refresh_token);
                 using (var response3 = httpClient.PostAsync(tokenUrl, new FormUrlEncodedContent(tokenParams)).Result)
                 {
                     var json = response3.Content.ReadAsStringAsync().Result;
                     var auth = JsonConvert.DeserializeObject<CrmAuth>(json);
                     if (auth == null)
                         throw new Exception(json);
                     return auth;
                 }
             }
         }

         /// <summary>
         /// 验证参数
         /// </summary>
         /// <param name="adfsUri"></param>
         /// <param name="resource"></param>
         /// <param name="clientId"></param>
         /// <param name="redirectUri"></param>
         /// <param name="userName"></param>
         /// <param name="password"></param>
         private static void VerifyParams(string adfsUri, string resource, string clientId, string redirectUri, string userName, string password)
         {
             if (string.IsNullOrWhiteSpace(adfsUri))
                 throw new ArgumentNullException(nameof(adfsUri));
             if (string.IsNullOrWhiteSpace(nameof(resource)))
                 throw new ArgumentNullException(resource);
             if (string.IsNullOrWhiteSpace(clientId))
                 throw new ArgumentNullException(nameof(clientId));
             if (string.IsNullOrWhiteSpace(redirectUri))
                 throw new ArgumentNullException(nameof(redirectUri));
             if (string.IsNullOrWhiteSpace(userName))
                 throw new ArgumentNullException(nameof(userName));
             if (string.IsNullOrWhiteSpace(password))
                 throw new ArgumentNullException(nameof(password));
         }

         /// <summary>
         /// 构建ADFS CODE地址
         /// </summary>
         /// <param name="adfsUri"></param>
         /// <param name="resource"></param>
         /// <param name="clientId"></param>
         /// <param name="redirectUri"></param>
         /// <returns></returns>
         private static string BuildCodeUrl(string adfsUri, string resource, string clientId, string redirectUri)
         {

             if (!adfsUri.EndsWith("/"))
                 adfsUri = adfsUri + "/";
             var url = $"{adfsUri}adfs/oauth2/authorize";

             var response_type = "code";

             var sb = new StringBuilder();
             sb.Append(url);
             sb.Append("?");
             sb.Append($"response_type={response_type}");
             sb.Append("&");
             sb.Append($"client_id={clientId}");
             sb.Append("&");
             sb.Append($"redirect_uri={redirectUri}");
             sb.Append("&");
             sb.Append($"resource={resource}");
             url = sb.ToString();
             return url;
         }

         /// <summary>
         /// 构建ADFS TOKEN地址
         /// </summary>
         /// <param name="adfsUri"></param>
         /// <returns></returns>
         private static string BuildTokenUrl(string adfsUri)
         {
             return $"{adfsUri}adfs/oauth2/token";
         }

         /// <summary>
         /// 构建请求Code参数
         /// </summary>
         /// <param name="userName"></param>
         /// <param name="password"></param>
         /// <returns></returns>
         private static List<KeyValuePair<string, string>> BuildCodeParams(string userName, string password)
         {
             var list = new List<KeyValuePair<string, string>>()
             {
                 new KeyValuePair<string, string>("UserName",userName),
                 new KeyValuePair<string, string>("Password",password),
                 new KeyValuePair<string, string>("Kmsi","true"),
                 new KeyValuePair<string, string>("AuthMethod","FormsAuthentication")
             };
             return list;
         }

         /// <summary>
         /// 构建请求Token参数
         /// </summary>
         /// <param name="clientId"></param>
         /// <param name="code"></param>
         /// <param name="resource"></param>
         /// <param name="redirectUri"></param>
         /// <returns></returns>
         private static List<KeyValuePair<string, string>> BuildTokenParams(string clientId, string code, string resource, string redirectUri)
         {
             var list = new List<KeyValuePair<string, string>>
             {
                 new KeyValuePair<string, string>("grant_type", "authorization_code"),
                 new KeyValuePair<string, string>("client_id", clientId),
                 new KeyValuePair<string, string>("code", code),
                 new KeyValuePair<string, string>("resource", resource),
                 new KeyValuePair<string, string>("redirect_uri", redirectUri)
             };
             return list;
         }

         /// <summary>
         /// 构建请求刷新Token参数
         /// </summary>
         /// <param name="refresh_token"></param>
         /// <returns></returns>
         private static List<KeyValuePair<string, string>> BuildRefreshTokenParams(string refresh_token)
         {
             var list = new List<KeyValuePair<string, string>>
             {
                 new KeyValuePair<string, string>("grant_type", "refresh_token"),
                 new KeyValuePair<string, string>("refresh_token", refresh_token),
             };
             return list;
         }

     }