上传文件并验证文件扩展名和文件大小 MVC 5

我使用下面的代码来上传并检查文件扩展名和文件大小

Update 2控制器

 public ActionResult Create([Bind(Include = "anak_ID,Pubdate,kind,title,file,details,link")] HttpPostedFileBase file, announcement announcement)
    {
        if (ModelState.IsValid)
        {
            db.announcement.Add(announcement);
            db.SaveChanges();
            TempData["notice"] = "Data saved";

            var allowedExtensions = new[] { ".pdf", ".zip", ".rar" };

            if (file!= null && file.ContentLength > 0)
            {
                var checkextension = Path.GetExtension(file.FileName).ToLower();


                if (itm.Contains(checkextension))
                    {
                        var extension = Path.GetExtension(file.FileName);
                        var path = Path.Combine(Server.MapPath("~/Content/AnnFiles/" + "announcement_" + announcement.anak_ID + extension));

                        //save File
                        file.SaveAs(path);

                        //prepere announcement
                        announcement.file= @"announcement_" + announcement.anak_ID + extension;


                        //Code for Save data to announcement.

                        db.SaveChanges();
                        TempData["notice"] = "OK! the file is uploaded";
                    }
                    else
                    {

                        TempData["notice"] = "Select pdf or zip or rar less than 20Μ";

                    }

            }

            return RedirectToAction("Create", announcement);


        }

        return View(announcement);
    }

创建视图文件字段。

 <div class="form-group">
        @Html.LabelFor(model => model.file, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-8">
            @Html.EditorFor(model => model.file, new { htmlAttributes = new { @class = "input-file", type = "file", name = "file"} })

        </div>
    </div>

创建视图（我显示消息的部分）。

  @if (TempData["notice"] != null)
    {
        <div class="alert alert-danger fade in">
            <a href="#" class="close" data-dismiss="alert">&times;</a>
            @TempData["notice"]
        </div>
    }

它将记录保存在数据库中，但在文件字段中保存“System.Web.HttpPostedFileWrapper”

当我将 if 语句从

 if (file != null && file .ContentLength > 0)

to

if (file != null && file .ContentLength > 0 && allowedExtensions.Contains(Path.GetExtension(file .FileName).ToLower()) && file .ContentLength <= (20 * 1024))

所以要检查文件扩展名和文件大小。

另一个问题是它总是显示消息 “选择小于20μ的pdf或zip或rar”并保存记录。我怀疑是因为 System.Web.HttpPostedFileWrapper 值。我想要实现的是当我选择不允许的扩展名和表中的文件名时不保存记录。 先感谢您

看看这些代码。

添加.png用于测试，您可以将其删除。

var allowedExtensions = new[] { ".pdf", ".zip", ".rar" };
var checkextension = Path.GetExtension(file.FileName).ToLower();

if (!allowedExtensions.Contains(checkextension))
{
    TempData["notice"] = "Select pdf or zip or rar less than 20Μ";
}

foreach (var itm in allowedExtensions)
{
    if (itm.Contains(checkextension))
    {
        db.announcement.Add(announcement);
        dbo.SaveChanges();
    }
}

if (file != null && file.ContentLength > 0)
{
    foreach (var itm in allowedExtensions)
    {
        if (itm.Contains(checkextension))
        {
            var extension = Path.GetExtension(file.FileName);
            var path = Path.Combine(Server.MapPath("~/Content/AnnFiles/" + "announcement_" + announcement.anak_ID + extension));

            //save File
            file.SaveAs(path);

            //prepere announcement
            announcement.file = @"announcement_" + announcement.anak_ID + extension;


            //Code for Save data to announcement.

            db.SaveChanges();
            TempData["notice"] = "OK! the file is uploaded";
        }
    }
}