在视图中：

<form action="Categories/Upload" enctype="multipart/form-data" method="post">
    <input type="file" name="Image">
    <input type="submit" value="Save">
</form>

而控制器中的以下代码：

public ActionResult Upload()
{
    foreach (string file in Request.Files)
    {
       var hpf = this.Request.Files[file];
       if (hpf.ContentLength == 0)
       {
            continue;
       }

       string savedFileName = Path.Combine(
                AppDomain.CurrentDomain.BaseDirectory, "PutYourUploadDirectoryHere");
                savedFileName = Path.Combine(savedFileName, Path.GetFileName(hpf.FileName));

        hpf.SaveAs(savedFileName);
    }

    ...
}

检查我的解决方案

public string SaveFile(HttpPostedFileBase uploadfile, string saveInDirectory="/", List<string> acceptedExtention =null)
{
    acceptedExtention = acceptedExtention ?? new List<String>() {".png", ".Jpeg"};//optional arguments

    var extension = Path.GetExtension(uploadfile.FileName).ToLower();

    if (!acceptedExtention.Contains(extension))
    {
        throw new UserFriendlyException("Unsupported File type");
    }
    var tempPath = GenerateDocumentPath(uploadfile.FileName, saveInDirectory);
    FileHelper.DeleteIfExists(tempPath);
    uploadfile.SaveAs(tempPath);

    var fileName = Path.GetFileName(tempPath);
    return fileName;
}

private string GenerateDocumentPath(string fileName, string saveInDirectory)
{
    System.IO.Directory.CreateDirectory(Server.MapPath($"~/{saveInDirectory}"));
    return Path.Combine(Server.MapPath($"~/{saveInDirectory}"), Path.GetFileNameWithoutExtension(fileName) +"_"+ DateTime.Now.Ticks + Path.GetExtension(fileName));
}

在基本控制器中添加这些函数，以便可以在所有控制器中使用它们

检查如何使用它

SaveFile(view.PassportPicture,acceptedExtention:new List<String>() { ".png", ".Jpeg"},saveInDirectory: "content/img/PassportPicture");

下面是一个完整的例子

[HttpPost]
public async Task<JsonResult> CreateUserThenGenerateToken(CreateUserViewModel view)
{// CreateUserViewModel contain two properties of type HttpPostedFileBase  
    string passportPicture = null, profilePicture = null;
    if (view.PassportPicture != null)
    {
        passportPicture = SaveFile(view.PassportPicture,acceptedExtention:new List<String>() { ".png", ".Jpeg"},saveInDirectory: "content/img/PassportPicture");
    }
    if (view.ProfilePicture != null)
    {
        profilePicture = SaveFile(yourHttpPostedFileBase, acceptedExtention: new List<String>() { ".png", ".Jpeg" }, saveInDirectory: "content/img/ProfilePicture");
    }
    var input = view.MapTo<CreateUserInput>();
    input.PassportPicture = passportPicture;
    input.ProfilePicture = profilePicture;


    var getUserOutput = await _userAppService.CreateUserThenGenerateToken(input);
    return new AbpJsonResult(getUserOutput);
    //return Json(new AjaxResponse() { Result = getUserOutput, Success = true });

}

下面是我的工作示例：

[HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Create(Product product, HttpPostedFileBase file)
    {
        if (!ModelState.IsValid)
            return PartialView("Create", product);
        if (file != null)
        {

            var fileName = Path.GetFileName(file.FileName);
            var guid = Guid.NewGuid().ToString();
            var path = Path.Combine(Server.MapPath("~/Content/Uploads/ProductImages"), guid + fileName);
            file.SaveAs(path);
            string fl = path.Substring(path.LastIndexOf("\\"));
            string[] split = fl.Split('\\');
            string newpath = split[1];
            string imagepath = "Content/Uploads/ProductImages/" + newpath;
            using (MemoryStream ms = new MemoryStream())
            {
                file.InputStream.CopyTo(ms);
                byte[] array = ms.GetBuffer();
            }
            var nId = Guid.NewGuid().ToString();
            // Save record to database
            product.Id = nId;
            product.State = 1;
            product.ImagePath = imagepath;
            product.CreatedAt = DateTime.Now;
            db.Products.Add(product);
            await db.SaveChangesAsync();
            TempData["message"] = "ProductCreated";

            //return RedirectToAction("Index", product);
        }
        // after successfully uploading redirect the user
        return Json(new { success = true });
    }

使用formdata上载文件

.cshtml文件

     var files = $("#file").get(0).files;
     if (files.length > 0) {
                data.append("filekey", files[0]);}


   $.ajax({
            url: '@Url.Action("ActionName", "ControllerName")', type: "POST", processData: false,
            data: data, dataType: 'json',
            contentType: false,
            success: function (data) {
                var response=data.JsonData;               
            },
            error: function (er) { }

        });

服务器端代码

if (System.Web.HttpContext.Current.Request.Files.AllKeys.Any())
                {
                    var pic = System.Web.HttpContext.Current.Request.Files["filekey"];
                    HttpPostedFileBase filebase = new HttpPostedFileWrapper(pic);
                    var fileName = Path.GetFileName(filebase.FileName);


                    string fileExtension = System.IO.Path.GetExtension(fileName);

                    if (fileExtension == ".xls" || fileExtension == ".xlsx")
                    {
                        string FileName = Guid.NewGuid().GetHashCode().ToString("x");
                        string dirLocation = Server.MapPath("~/Content/PacketExcel/");
                        if (!Directory.Exists(dirLocation))
                        {
                            Directory.CreateDirectory(dirLocation);
                        }
                        string fileLocation = Server.MapPath("~/Content/PacketExcel/") + FileName + fileExtension;
                        filebase.SaveAs(fileLocation);
}
}

保存多个文件的简单方法

cshtml

@using (Html.BeginForm("Index","Home",FormMethod.Post,new { enctype = "multipart/form-data" }))
{
    <label for="file">Upload Files:</label>
    <input type="file" multiple name="files" id="files" /><br><br>
    <input type="submit" value="Upload Files" />
    <br><br>
    @ViewBag.Message
}

控制器

[HttpPost]
        public ActionResult Index(HttpPostedFileBase[] files)
        {
            foreach (HttpPostedFileBase file in files)
            {
                if (file != null && file.ContentLength > 0)
                    try
                    {
                        string path = Path.Combine(Server.MapPath("~/Files"), Path.GetFileName(file.FileName));
                        file.SaveAs(path);
                        ViewBag.Message = "File uploaded successfully";
                    }
                    catch (Exception ex)
                    {
                        ViewBag.Message = "ERROR:" + ex.Message.ToString();
                    }

                else
                {
                    ViewBag.Message = "You have not specified a file.";
                }
            }
            return View();
        }

如果有人想用Ajax上传多个文件，下面是我的文章在Asp.NetMVC中使用Ajax进行多文件上传