Gọi upload Multipart C#

 public void UploadMultiFilesTest()

        {

            var message = new HttpRequestMessage();

            var content = new MultipartFormDataContent();

            string[] fileUploadPaths = { @"C:\Users\Acer\Pictures\photo_2020-12-16_10-25-16.jpg" };

            int count = 0;

            foreach (string fileUploadPath in fileUploadPaths)

            {

                var filestream = new FileStream(fileUploadPath, FileMode.Open);

                var fileName = Path.GetFileName(fileUploadPath);

                content.Add(new StreamContent(filestream), "file_" + (++count), fileName);

            }

            content.Add(new StringContent("this is value"), "json_key");

            var client = new HttpClient();

            client.PostAsync("http://localhost:6764/MediaUpload", content).ContinueWith(task =>

            {

                if (task.Result.IsSuccessStatusCode)

                {

                    //

                }

            });

        }