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Question

所以我试图弄清楚如何更新cshtml文件中的特定元素，例如标签。

因此标签目前是<p>File ready for upload</p>，当我点击按钮时，我希望它更改为<p>Files must be a <b>.jpeg</b> <b>.jpg</b> <b>.png</b> <b>.bmp</b> file format.</p>

我已经有逻辑工作上传并且只允许这些文件格式，我只想通过更改我上面说过的标签来提醒用户他们需要它。我知道它会在catch (exception)中，因为我使用的是try catch语句。

我的代码： 控制器： FileSharings.cs

public ActionResult Create([Bind(Include = "Id,Title,Description,FileName,FileType,FileSize,Author,DateUploaded")] FileSharing fileSharing)
    {
        HttpPostedFileBase file = Request.Files.Get(0);
        string fileName = Path.GetFileName(file.FileName);
        string filePath = Path.Combine(Server.MapPath("~/Assets/"), fileName);
        var allowedExtensions = new string[] { ".jpeg", ".png", ".jpg", ".bmp" };
        string fileExtension = Path.GetExtension(file.FileName).ToLower();
        string extension = Path.GetExtension(file.FileName);

        try
        {
            if (Request.Files.Count > 0 && (ModelState.IsValid) && (allowedExtensions.Contains(extension)))
            {
                file.SaveAs(filePath);
                FileInfo fileInfo = new FileInfo(filePath);
                fileSharing.FileType = fileInfo.Extension.Remove(0, 1).ToLower();
                fileSharing.DateUploaded = DateTime.Now;
                fileSharing.FileName = fileName;
                fileSharing.FileSize = fileInfo.Length.ToString();
                fileSharing.Author = User.Identity.Name;
                db.FileSharing.Add(fileSharing);
                db.SaveChanges();
            }
        }

        catch (Exception)
        {

        }

        return View(fileSharing);
    }

Answer 1

＃

public ActionResult Index()
{
    ViewBag.MyMessageToUsers = "Files must be a <b>.jpeg</b> <b>.jpg</b> <b>.png</b> <b>.bmp</b> file format";;

    return View();
}

CSHTML.cs

@ViewBag.MyMessageToUsers

Answer 2

JQuery解决方案

  // get file name
    var filename = $("#file_input").val();

    // get extension
    var ext = filename.replace(/^.*\./, '');

   // Validate
   if($.inArray( ext, [ ".jpeg", ".png", ".jpg", ".bmp" ] ) == -1)
        $("#label_error").html("file extension not matched");