c# - MVC-4 文件上传成功消息

Question

我在上传文件后显示成功消息时遇到了一些问题。

我首先尝试使用 ViewBag.Message ，它运行良好并在文件上传后显示成功消息，这正是我想要的。但是后来我找不到方法，几秒钟后将该消息更改回:“选择要上传的文件!” ，以便用户了解他现在可以上传新文件。

我尝试实现一个 javascript 功能来处理成功消息。这样做的问题是在文件上传完成之前会显示成功消息，这是不好的，如果它是一个非常小的文件，消息只会显示一毫秒。

您对我如何微调它有什么建议吗？我不确定我是否应该尝试使用 javascript 或 viewbag 或其他东西进一步工作？

我正在寻找的是成功上传后显示约 5 秒的成功消息，然后再次变回“选择要上传的文件消息”。

https://github.com/xoxotw/mvc_fileUploader

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Web;
using System.Web.Mvc;

namespace Mvc_fileUploader.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            //ViewBag.Message = "Choose a file to upload !";
            return View("FileUpload");
        }

        [HttpPost]
        public ActionResult FileUpload(HttpPostedFileBase fileToUpload)
        {

            if (ModelState.IsValid)
            {
                if (fileToUpload != null && fileToUpload.ContentLength > (1024 * 1024 * 2000))  // 1MB limit
                {
                    ModelState.AddModelError("fileToUpload", "Your file is to large. Maximum size allowed is 1MB !");
                }

                else
                {
                    string fileName = Path.GetFileName(fileToUpload.FileName);
                    string directory = Server.MapPath("~/fileUploads/");

                    if (!Directory.Exists(directory))
                    {
                        Directory.CreateDirectory(directory);
                    }

                    string path = Path.Combine(directory, fileName);
                    fileToUpload.SaveAs(path);

                    ModelState.Clear();
                    //ViewBag.Message = "File uploaded successfully !";

                 }
            }

            return View("FileUpload");

        }



        public ActionResult About()
        {
            ViewBag.Message = "Your app description page.";

            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";

            return View();
        }
    }
}

文件上传 View :

@{
    ViewBag.Title = "FileUpload";
}

<h2>FileUpload</h2>

<h3>Upload a File:</h3>


@using (Html.BeginForm("FileUpload", "Home", FormMethod.Post, new {enctype = "multipart/form-data"}))
{ 
    @Html.ValidationSummary();
    <input type="file" name="fileToUpload" /><br />
    <input type="submit" onclick="successMessage()" name="Submit" value="upload" />  
    //@ViewBag.Message
    <span id="sM">Choose a file to upload !</span>
}


<script>
    function successMessage()
    {
        x = document.getElementById("sM");
        x.innerHTML = "File upload successful !";
    }
</script>

Answer 1

几件事，

首先，您需要一个模型来指示上传成功，我们可以在您的实例中使用 bool 来指示它。

将此添加到 View 的顶部:

@model bool

然后你可以这样做(保持你的观点不变):

@{
    ViewBag.Title = "FileUpload";
}

<h2>FileUpload</h2>

<h3>Upload a File:</h3>

@using (Html.BeginForm("FileUpload", "Home", FormMethod.Post, new {enctype = "multipart/form-data"}))
{ 
    @Html.ValidationSummary();
    <input type="file" name="fileToUpload" /><br />
    <input type="submit" onclick="successMessage()" name="Submit" value="upload" />  

    <span id="sM">Choose a file to upload !</span>
}

我们可以根据模型值在JS中操作sM

<script>

    @if(Model)
    {
        var x = document.getElementById("sM");
        x.innerHTML = "File upload successful !";
        setTimeout("revertSuccessMessage()", 5000);
    }

    function revertSuccessMessage()
    {
        var x = document.getElementById("sM");
        x.innerHTML = "Choose a file to upload !";
    }
</script>

然后在操作方法的 else 语句中，确保成功时返回 true，否则返回 false。像这样

else
{
    string fileName = Path.GetFileName(fileToUpload.FileName);
    string directory = Server.MapPath("~/fileUploads/");

    if (!Directory.Exists(directory))
    {
        Directory.CreateDirectory(directory);
    }

    string path = Path.Combine(directory, fileName);
    fileToUpload.SaveAs(path);

    ModelState.Clear();

    return View("FileUpload", true);
}

return View("FileUpload", false);