C# 后台实现一次上传多个文件

 string result="";   
 string urlUploadMultiFile = "http://127.0.0.1:8090/overload/uploaddata.action";//上传地址
 //赋值
 infoData.id="123";
 infoData.name= "张三";
 infoData.date= "2020-10-20 15:50:00";
 string jsonParam = JsonConvert.SerializeObject(infoData);
 List<string> fileLst = new List<string>();
 fileLst.Add("1.jpg");
 fileLst.Add("2.jpg");
 fileLst.Add("3.jpg");
 fileLst.Add(z"4video.mp4");
 string[] filesArray = fileLst.ToArray();//strArray=[str0,str1,str2]//转数组

 //调用
 if (UploadMultiFile(urlUploadMultiFile, jsonParam, filesArray, "application/octet-stream", "file") > 0)
 {
　　　　　　result="成功";
 }            

上传方法

 　　　　 /// <summary>
        /// 多文件上传
        /// </summary>
        /// <param name="url">请求路径</param>
        /// <param name="jsonParam">数据</param>
        /// <param name="files">图片路径</param>
        /// <param name="contentType"></param>
        /// <param name="paramFileName">对应的图片字段</param>
        /// <returns></returns>
        public static int UploadMultiFile(string url, string jsonParam, string[] files, string contentType, string paramFileName)
        {
           int result = -1;
            if (files.Length <= 0) return result;

            Dictionary<string, string> nvc = new Dictionary<string, string>();
            nvc.Add("queryParam", jsonParam);
            string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");//边界符
            byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("
--" + boundary + "
");//开始边界符
            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
            wr.ContentType = "multipart/form-data; boundary=" + boundary;
            wr.Method = "POST";
            wr.KeepAlive = true;
            wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
            Stream rs = wr.GetRequestStream();
            string formdataTemplate = "Content-Disposition: form-data; name="{0}"

{1}";
            foreach (string key in nvc.Keys)
            {
                rs.Write(boundarybytes, 0, boundarybytes.Length);//写入边界符
                string formitem = string.Format(formdataTemplate, key, nvc[key]);
                byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
                rs.Write(formitembytes, 0, formitembytes.Length);//写入数据
            }
            rs.Write(boundarybytes, 0, boundarybytes.Length);//写入边界符

            byte[] trailer = System.Text.Encoding.ASCII.GetBytes("
--" + boundary + "--
");

            for (int k = 0, k2 = files.Length; k < k2; k++)
            {
                string fname = paramFileName;
                string headerTemplate = "Content-Disposition: form-data; name="{0}"; filename="{1}"
Content-Type: {2}

";
                string header = string.Format(headerTemplate, fname, files[k], contentType);//写入字符串
                byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
                rs.Write(headerbytes, 0, headerbytes.Length);//写入文件

                FileStream fileStream = new FileStream(files[k], FileMode.Open, FileAccess.Read);
                byte[] buffer = new byte[4096];
                int bytesRead = 0;
                while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                {
                    rs.Write(buffer, 0, bytesRead);
                }
                fileStream.Close();
                if (k < k2 - 1) rs.Write(boundarybytes, 0, boundarybytes.Length);
            }
            rs.Write(trailer, 0, trailer.Length);
            rs.Close();
            WebResponse wresp = null;
            try
            {
                wresp = wr.GetResponse();
                Stream stream2 = wresp.GetResponseStream();
                StreamReader reader2 = new StreamReader(stream2);
                JObject resultJson = (JObject)JsonConvert.DeserializeObject(reader2.ReadToEnd());
                if (resultJson.Property("message") != null && resultJson["message"].ToString() == "操作成功")
                {
                    result = 1;
                    SysCfg.WriteLog("result：" + resultJson, false);
                }
                //result = reader2.ReadToEnd();
            }
            catch (Exception ex)
            {
                if (wresp != null)
                {
                    wresp.Close();
                    wresp = null;
                }
                SysCfg.WriteLog("UploadMultiFile,ex:" + ex.Message);
                result = -1;
            }
            finally
            {
                wr = null;
            }
            return result;
        }