ASP.Net 5 上传文件通过虚拟路径存储

  [HttpPost]
        public IActionResult ImportTeaching(IFormFile file)
        {
            string root = @"Temp/teachingfile/";
            string phyPayh = evn.MapPath(root);
            if (file != null)
            {
                var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
                var originalName = parsedContentDisposition.FileName.Replace("\"", "");
                file.SaveAs(phyPayh + originalName);
            }
            else
            {
                ModelState.AddModelError("", "没有选择文件");
                return View();
            }
            return RedirectToAction("Index");
        }

  [FromServices]
        public IHostingEnvironment evn { set; get; }