public class PictureController : Controller

    {

        private IHostingEnvironment hostingEnv;

        public PictureController(IHostingEnvironment env)

        {

            this.hostingEnv = env;

        }

        // GET: /<controller>/

        public IActionResult Index()

        {

            return View();

        }

        public IActionResult UploadFiles()

        {

            return View();

        }

        [HttpPost]

        public IActionResult UploadFiles(IList<IFormFile> files)

        {

            long size = ;

            foreach (var file in files)

            {

                var filename = ContentDispositionHeaderValue

                                .Parse(file.ContentDisposition)

                                .FileName

                                .Trim('"');
               //这个hostingEnv.WebRootPath就是要存的地址可以改下

                filename = hostingEnv.WebRootPath + $@"\{filename}";

                size += file.Length;

                using (FileStream fs = System.IO.File.Create(filename))

                {

                    file.CopyTo(fs);

                    fs.Flush();

                }

            }

            ViewBag.Message = $"{files.Count} file(s) /{ size}bytes uploaded successfully!";

             return View();

        }

    }

<form asp-action="UploadFiles"

                  asp-controller="Picture"

                  method="post"

                  enctype="multipart/form-data">

                <input type="file" name="files" multiple />

                <input type="submit" value="Upload Selected Files" />

 </form>

        public IActionResult UploadFilesAjax()

        {

            return View();

        }

        [HttpPost]

        public IActionResult UploadFilesAjax(string z)

        {

            long size = ;

            var files = Request.Form.Files;

            foreach (var file in files)

            {

                var filename = ContentDispositionHeaderValue

                                .Parse(file.ContentDisposition)

                                .FileName

                                .Trim('"');

                filename = @"C:\Users\lg.HL\Desktop" + $@"\{filename}";

                size += file.Length;

                using (FileStream fs = System.IO.File.Create(filename))

                {

                    file.CopyTo(fs);

                    fs.Flush();

                }

            }

            string message = $"{files.Count} file(s) / { size}bytes uploaded successfully!";

                return Json(message);

        }

<form method="post" enctype="multipart/form-data">

            <input type="file" id="files"

                   name="files" multiple />

            <input type="button"

                   id="upload"

                   value="Upload Selected Files" />

 </form>

<script type="text/javascript">

        $(document).ready(function () {

            $("#upload").click(function (evt) {

                var fileUpload = $("#files").get();

                var files = fileUpload.files;

                var data = new FormData();

                for (var i = ; i < files.length ; i++) {

                    data.append(files[i].name, files[i]);

                }

                $.ajax({

                    type: "POST",

                    url: "/Picture/UploadFilesAjax",

                    contentType: false,

                    processData: false,

                    data: data,

                    success: function (message) {

                        alert(message);

                    },

                    error: function () {

                        alert("There was error uploading files!");

                    }

                });

            });

        });

</script>