/// <summary>

        /// 重试

        /// </summary>

        public class RetryHandler : DelegatingHandler

        {

            private const int maxRetries = 3;

            /// <summary>

            /// 重试

            /// </summary>

            /// <param name="innerHandler"></param>

            public RetryHandler(HttpMessageHandler innerHandler)

                : base(innerHandler)

            { }

            /// <summary>

            /// 重试

            /// </summary>

            /// <param name="request"></param>

            /// <param name="cancellationToken"></param>

            /// <returns></returns>

            protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

            {

                HttpResponseMessage response = null;

                for (int i = 0; i < maxRetries; i++)

                {

                    response = await base.SendAsync(request, cancellationToken);

                    if (response.IsSuccessStatusCode)

                    {

                        return response;

                    }

                }

                return response;

            }

        }

 

使用：

var client = new HttpClient(new RetryHandler(new HttpClientHandler())