HttpClient封装方法

//post请求
        public static string PostRequest(string url, HttpContent data)
        {
            var handler = new HttpClientHandler() { UseCookies = false };
            HttpClient client = new HttpClient(handler);
            var message = new HttpRequestMessage(HttpMethod.Post, url);
            message.Content = data;
            //message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", GetRemoteToken());
            var response = client.SendAsync(message).Result;
            response.EnsureSuccessStatusCode();
            var result = response.Content.ReadAsStringAsync().Result;
            return result;
        }


 //发送文件
        public static void SendFile(string url,string path = @"C:\<filepath>\test.txt")
        {
            using (var client = new HttpClient())
            using (var content = new MultipartFormDataContent())
            {
                client.BaseAddress = new Uri("http://localhost");

                var fileContent1 = new ByteArrayContent(File.ReadAllBytes(path));
                fileContent1.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                {
                    FileName = Path.GetFileName(path)
                };
                content.Add(fileContent1);

                var result = client.PostAsync(url, content).Result;
            }
        }

    /// <summary>
    /// Http请求帮助类
    /// </summary>
    public class HttpHelper
    {
        /// <summary>
        /// 同步GET请求
        /// </summary>
        /// <param name="url"></param>
        /// <param name="headers"></param>
        /// <param name="timeout">请求响应超时时间，单位/s(默认100秒)</param>
        /// <returns></returns>
        public static string HttpGet(string url, Dictionary<string, string> headers = null, int timeout = 0)
        {
            using (HttpClient client = new HttpClient())
            {
                if (headers != null)
                {
                    foreach (KeyValuePair<string, string> header in headers)
                    {
                        client.DefaultRequestHeaders.Add(header.Key, header.Value);
                    }
                }
                if (timeout > 0)
                {
                    client.Timeout = new TimeSpan(0, 0, timeout);
                }
                Byte[] resultBytes = client.GetByteArrayAsync(url).Result;
                return Encoding.UTF8.GetString(resultBytes);
            }
        }
        /// <summary>
        /// 异步GET请求
        /// </summary>
        /// <param name="url"></param>
        /// <param name="headers"></param>
        /// <param name="timeout">请求响应超时时间，单位/s(默认100秒)</param>
        /// <returns></returns>
        public static async Task<string> HttpGetAsync(string url, Dictionary<string, string> headers = null, int timeout = 0)
        {
            using (HttpClient client = new HttpClient())
            {
                if (headers != null)
                {
                    foreach (KeyValuePair<string, string> header in headers)
                    {
                        client.DefaultRequestHeaders.Add(header.Key, header.Value);
                    }
                }
                if (timeout > 0)
                {
                    client.Timeout = new TimeSpan(0, 0, timeout);
                }
                Byte[] resultBytes = await client.GetByteArrayAsync(url);
                return Encoding.Default.GetString(resultBytes);
            }
        }


        /// <summary>
        /// 同步POST请求
        /// </summary>
        /// <param name="url"></param>
        /// <param name="postData"></param>
        /// <param name="headers"></param>
        /// <param name="contentType"></param>
        /// <param name="timeout">请求响应超时时间，单位/s(默认100秒)</param>
        /// <param name="encoding">默认UTF8</param>
        /// <returns></returns>
        public static string HttpPost(string url, string postData, Dictionary<string, string> headers = null, string contentType = null, int timeout = 0, Encoding encoding = null)
        {
            using (HttpClient client = new HttpClient())
            {
                client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36");
                if (headers != null)
                {
                    foreach (KeyValuePair<string, string> header in headers)
                    {
                        client.DefaultRequestHeaders.Add(header.Key, header.Value);
                    }
                }
                if (timeout > 0)
                {
                    client.Timeout = new TimeSpan(0, 0, timeout);
                }
                using (HttpContent content = new StringContent(postData ?? "", encoding ?? Encoding.UTF8))
                {
                    if (contentType != null)
                    {
                        content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue(contentType);
                    }
                    using (HttpResponseMessage responseMessage = client.PostAsync(url, content).Result)
                    {
                        Byte[] resultBytes = responseMessage.Content.ReadAsByteArrayAsync().Result;
                        return Encoding.UTF8.GetString(resultBytes);
                    }
                }
            }
        }

        /// <summary>
        /// 异步POST请求
        /// </summary>
        /// <param name="url"></param>
        /// <param name="postData"></param>
        /// <param name="headers"></param>
        /// <param name="contentType"></param>
        /// <param name="timeout">请求响应超时时间，单位/s(默认100秒)</param>
        /// <param name="encoding">默认UTF8</param>
        /// <returns></returns>
        public static async Task<string> HttpPostAsync(string url, string postData, Dictionary<string, string> headers = null, string contentType = null, int timeout = 0, Encoding encoding = null)
        {
            using (HttpClient client = new HttpClient())
            {
                client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36");
                if (headers != null)
                {
                    foreach (KeyValuePair<string, string> header in headers)
                    {
                        client.DefaultRequestHeaders.Add(header.Key, header.Value);
                    }
                }
                if (timeout > 0)
                {
                    client.Timeout = new TimeSpan(0, 0, timeout);
                }
                using (HttpContent content = new StringContent(postData ?? "", encoding ?? Encoding.UTF8))
                {
                    if (contentType != null)
                    {
                        content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue(contentType);
                    }
                    using (HttpResponseMessage responseMessage = await client.PostAsync(url, content))
                    {
                        Byte[] resultBytes = await responseMessage.Content.ReadAsByteArrayAsync();
                        return Encoding.UTF8.GetString(resultBytes);
                    }
                }
            }
        }
    }

　　

   //httpcontent类型
       //json
            HttpContent content1 = new StringContent("{a:1,b:2}", Encoding.UTF8, "application/json");
       //from
            HttpContent content2 = new FormUrlEncodedContent(new Dictionary<string, string>()
           {
              {"email", "1"},
              {"pwd","11"}
           });