public async Task <IHttpActionResult> UploadDocument(int targetFolder)
    {
        var uploadFileService = new UploadFileService();
        UploadProcessingResult uploadResult = await uploadFileService.HandleRequest(Request);

        if (uploadResult.IsComplete)
        {
            // do other stuff here after file upload complete
            return(Ok());
        }

        return(Ok(HttpStatusCode.Continue));
    }
        public async Task <IHttpActionResult> LargeFile()
        {
            HttpContext      _context          = HttpContext.Current;
            string           root              = _context.Server.MapPath("~/App_Data");
            FileUploadHelper uploadFileService = new FileUploadHelper(root);

            try
            {
                UploadProcessingResult uploadResult = await uploadFileService.HandleRequest(Request);
            }
            catch (Exception ex)
            {
                return(Json(new { success = false, message = ex.Message, stack = ex.StackTrace }));
            }
            return(Json(new { success = true, message = "file uploaded successfully" }));
        }