C#使用企业微信群聊机器人API

    public class OperationResult
    {
        public bool IsSuccess { get; set; }
        public int ErrorCode { get; set; }
        public string Content { get; set; }
    }

    internal static class TextType
    {
        internal static string RobotUrl { get; set; }
        internal static async Task<OperationResult> SendText(string text)
        {
            OperationResult result = new OperationResult();
            string recData = await PostAsync(RobotUrl, getTextTypeJson(text));
            dynamic json = JsonConvert.DeserializeObject<dynamic>(recData);
            int errorcode = json.errcode;
            string errmsg = json.errmsg;
            result.IsSuccess = errorcode == 0;
            result.ErrorCode = errorcode;
            result.Content = errmsg;
            return result;
        }

        internal static async Task<OperationResult> SendTextFile(string text)
        {
            OperationResult result = new OperationResult();
            string recData = await PostAsync(RobotUrl, getSendFileTypeJson(text));
            dynamic json = JsonConvert.DeserializeObject<dynamic>(recData);
            int errorcode = json.errcode;
            string errmsg = json.errmsg;
            result.IsSuccess = errorcode == 0;
            result.ErrorCode = errorcode;
            result.Content = errmsg;
            return result;
        }

        static string getTextTypeJson(string text)
        {
            var json = new
            {
                msgtype = "text",
                text = new
                {
                    content = text,
                }
            };
            return JsonConvert.SerializeObject(json);
        }

        static string getSendFileTypeJson(string media_id)
        {
            var json = new
            {
                msgtype = "file",
                file = new
                {
                    media_id = media_id
                }
            };
            return JsonConvert.SerializeObject(json);
        }

        static async Task<string> PostAsync(string url, string data)
        {
            byte[] postdata = Encoding.UTF8.GetBytes(data);
            WebRequest request = WebRequest.Create(url);
            request.Method = "POST";
            request.ContentType = "application/json";
            request.ContentLength = postdata.Length;

            using (Stream requestStream = request.GetRequestStream())
            {
                requestStream.Write(postdata, 0, postdata.Length);
            }
            string resData = "";
            using (WebResponse response = await request.GetResponseAsync())
            {
                using (Stream responseStream = response.GetResponseStream())
                {
                    using (StreamReader sr = new StreamReader(responseStream))
                    {
                        resData = sr.ReadToEnd();
                    }
                }
            }
            return resData;
        }
    }

    internal static class ImageType
    {
        internal static string RobotUrl { get; set; }
        internal static async Task<OperationResult> SendPhoto( string FilePath)
        {
            OperationResult result = new OperationResult();
            bool isphoto = IsPhoto(FilePath);
            if (!isphoto)
            {
                result.IsSuccess = false;
                result.ErrorCode = -1;
                result.Content = "不是图片文件";
                return result;
            }
            long filebytessize = new FileInfo(FilePath).Length;
            if (filebytessize >= 1024 * 1024 * 20)
            {
                result.IsSuccess = false;
                result.ErrorCode = -2;
                result.Content = "文件最大不能超过2M";
                return result;
            }
            Image image = Image.FromFile(FilePath);
            return await SendPhoto(RobotUrl, image);
        }

        static async Task<OperationResult> SendPhoto(string RobotUrl, Image image)
        {
            OperationResult result = new OperationResult();
            string recData = await PostAsync(RobotUrl, getImageTypeJson(image));
            dynamic json = JsonConvert.DeserializeObject<dynamic>(recData);
            int errorcode = json.errcode;
            string errmsg = json.errmsg;
            result.IsSuccess = errorcode == 0;
            result.ErrorCode = errorcode;
            result.Content = errmsg;
            return result;
        }

        static bool IsPhoto(string FilePath)
        {
            string extension = Path.GetExtension(FilePath);

            // 支持的图片文件扩展名列表
            string[] imageExtensions = { ".jpg", ".png" };
            if (imageExtensions.Contains(extension.ToLower()))
            {
                // 使用Image类尝试加载图片文件
                try
                {
                    using (var image = Image.FromFile(FilePath))
                    {
                        return true;
                    }
                }
                catch
                {
                    // 如果加载图片文件失败，则说明该文件不是有效的图片文件
                    return false;
                }
            }
            return false;
        }

        static async Task<string> PostAsync(string url, string data)
        {
            byte[] postdata = Encoding.UTF8.GetBytes(data);
            WebRequest request = WebRequest.Create(url);
            request.Method = "POST";
            request.ContentType = "application/json";
            request.ContentLength = postdata.Length;

            using (Stream requestStream = request.GetRequestStream())
            {
                requestStream.Write(postdata, 0, postdata.Length);
            }
            string resData = "";
            using (WebResponse response = await request.GetResponseAsync())
            {
                using (Stream responseStream = response.GetResponseStream())
                {
                    using (StreamReader sr = new StreamReader(responseStream))
                    {
                        resData = sr.ReadToEnd();
                    }
                }
            }
            return resData;
        }

        static string ImageToBase64(Image image)
        {
            using (MemoryStream memoryStream = new MemoryStream())
            {
                image.Save(memoryStream, image.RawFormat);
                byte[] imageBytes = memoryStream.ToArray();
                string base64String = Convert.ToBase64String(imageBytes);
                return base64String;
            }
        }
        static string GetImageMD5(Image image)
        {
            using (MemoryStream memoryStream = new MemoryStream())
            {
                image.Save(memoryStream, image.RawFormat);
                byte[] imageBytes = memoryStream.ToArray();

                using (MD5 md5 = MD5.Create())
                {
                    byte[] hashBytes = md5.ComputeHash(imageBytes);
                    string md5Hash = BitConverter.ToString(hashBytes).Replace("-", "").ToLower();
                    return md5Hash;
                }
            }
        }

        static string getImageTypeJson(Image image)
        {
            var json = new
            {
                msgtype = "image",
                image = new
                {
                    base64 = ImageToBase64(image),
                    md5 = GetImageMD5(image)
                }
            };
            return JsonConvert.SerializeObject(json);
        }
    }

public delegate void UpLoadProgress(int percentage);
    public delegate void UpLoadCompleteDel();
    internal static class FileType
    {
        static string url = "https://qyapi.weixin.qq.com/cgi-bin/webhook/upload_media?key={0}&type=file";
        internal static string upLoadFileKey { get; set; }


        public static event UpLoadProgress upLoadProgressEvent;
        public static event UpLoadCompleteDel upLoadCompleteDelEvent;
        internal static async Task<OperationResult> SendFile(string FilePath)
        {
            string Posturl = string.Format(url, upLoadFileKey);
            OperationResult result = new OperationResult();
            FormItemModel formItem = new FormItemModel()
            {
                Key = Path.GetFileName(FilePath),
                FileContent = File.OpenRead(FilePath),
                FileName = Path.GetFileName(FilePath),
                Value = ""
            };
            if (formItem.FileContent.Length >= 1024 * 1024 * 20)
            {
                result.IsSuccess = false;
                result.ErrorCode = -2;
                result.Content = "文件最大不能超过20M";
            }
            string re = await PostForm(Posturl, formItem);
            dynamic jObect = JsonConvert.DeserializeObject<dynamic>(re);
            string media_id = jObect.media_id;
            if (media_id == null)
            {
                result.IsSuccess = false;
                result.ErrorCode = jObect.errcode;
                result.Content = jObect.errmsg;
                return result;
            }
            return await TextType.SendTextFile(media_id);
        }


        /// <summary>
        /// 使用Post方法获取字符串结果
        /// </summary>
        /// <param name="url"></param>
        /// <param name="formItems">Post表单内容</param>
        /// <param name="cookieContainer"></param>
        /// <param name="timeOut">默认20秒</param>
        /// <param name="encoding">响应内容的编码类型（默认utf-8）</param>
        /// <returns></returns>
        static async Task<string> PostForm(string url, FormItemModel formItems, CookieContainer cookieContainer = null, string refererUrl = null, Encoding encoding = null, int timeOut = 60000)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            #region 初始化请求对象
            request.Method = "POST";
            request.Timeout = timeOut;
            request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
            request.KeepAlive = true;
            request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36";
            if (!string.IsNullOrEmpty(refererUrl))
                request.Referer = refererUrl;
            if (cookieContainer != null)
                request.CookieContainer = cookieContainer;
            #endregion

            string boundary = "----" + DateTime.Now.Ticks.ToString("x");//分隔符
            request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
            //请求流
            var postStream = new MemoryStream();
            #region 处理Form表单请求内容
            //是否用Form上传文件
            var formUploadFile = formItems != null;
            if (formUploadFile)
            {
                //文件数据模板
                string fileFormdataTemplate =
                    "\r\n--" + boundary +
                    "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"" +
                    "\r\nContent-Type: application/octet-stream" +
                    "\r\n\r\n";
                //文本数据模板
                string dataFormdataTemplate =
                    "\r\n--" + boundary +
                    "\r\nContent-Disposition: form-data; name=\"{0}\"" +
                    "\r\n\r\n{1}";
                string formdata = null;
                if (formItems.IsFile)
                {
                    //上传文件
                    formdata = string.Format(
                        fileFormdataTemplate,
                        formItems.Key, //表单键
                        formItems.FileName);
                }
                else
                {
                    //上传文本
                    formdata = string.Format(
                        dataFormdataTemplate,
                        formItems.Key,
                        formItems.Value);
                }

                //统一处理
                byte[] formdataBytes = null;
                //第一行不需要换行
                if (postStream.Length == 0)
                    formdataBytes = Encoding.UTF8.GetBytes(formdata.Substring(2, formdata.Length - 2));
                else
                    formdataBytes = Encoding.UTF8.GetBytes(formdata);
                postStream.Write(formdataBytes, 0, formdataBytes.Length);

                //写入文件内容
                if (formItems.FileContent != null && formItems.FileContent.Length > 0)
                {
                    using (var stream = formItems.FileContent)
                    {
                        byte[] buffer = new byte[1024];
                        int bytesRead = 0;
                        while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)
                        {
                            postStream.Write(buffer, 0, bytesRead);
                        }
                    }
                }
                //结尾
                var footer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
                postStream.Write(footer, 0, footer.Length);

            }
            else
            {
                request.ContentType = "application/x-www-form-urlencoded";
            }
            #endregion

            request.ContentLength = postStream.Length;

            #region 输入二进制流
            if (postStream != null)
            {
                postStream.Position = 0;
                //直接写入流
                Stream requestStream = request.GetRequestStream();

                byte[] buffer = new byte[1024];
                int bytesRead = 0;
                long totalBytesRead = 0;
                await Task.Run(() =>
                {
                    while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) != 0)
                    {
                        requestStream.Write(buffer, 0, bytesRead);
                        totalBytesRead += bytesRead;

                        // 计算上传进度
                        int progressPercentage = (int)((totalBytesRead * 100) / postStream.Length);
                        upLoadProgressEvent?.Invoke(progressPercentage);
                    }
                });
                ////debug
                //postStream.Seek(0, SeekOrigin.Begin);
                //StreamReader sr = new StreamReader(postStream);
                //var postStr = sr.ReadToEnd();
                postStream.Close();//关闭文件访问
                upLoadCompleteDelEvent?.Invoke();
            }
            #endregion
            try
            {
                HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync();
                if (cookieContainer != null)
                {
                    response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
                }

                return await Task.Run(() =>
                {
                    using (Stream responseStream = response.GetResponseStream())
                    {
                        using (StreamReader myStreamReader = new StreamReader(responseStream, encoding ?? Encoding.UTF8))
                        {
                            string retString = myStreamReader.ReadToEnd();
                            return retString;
                        }
                    }
                });
            }
            catch (Exception ex)
            {
                var json = new
                {
                    errcode = -4,
                    errmsg = ex.Message,
                };
                return json.ToString();
            }
        }
    }