MVC实现文件下载

□ 思路

点击一个链接，把该文件的Id传递给控制器方法，遍历文件夹所有文件，根据ID找到对应文件，并返回FileResult类型。

与文件相关的Model:

namespace MvcApplication1.Models
{
    public class FileForDownload
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Path { get; set; }
    }
}

写一个针对文件的帮助类，遍历指定文件夹的所有文件，返回FileForDownload集合类型。在项目根目录下创建Files文件夹，存放下载文件。

using System.Collections.Generic;
using System.IO;
using System.Web.Hosting;
using MvcApplication1.Models;

namespace MvcApplication1.Helper
{
    public class FileHelper
    {
        public List<FileForDownload> GetFiles()
        {
            List<FileForDownload> result = new List<FileForDownload>();
            DirectoryInfo dirInfo = new DirectoryInfo(HostingEnvironment.MapPath("~/Files"));

            int i = 0;
            foreach (var item in dirInfo.GetFiles())
            {
                result.Add(new FileForDownload()
                {
                    Id = i + 1,
                    Name = item.Name,
                    Path = dirInfo.FullName + @"" + item.Name
                });
                i++;
            }
            return result;
        }
    }
}

HomeController中：

using System;
using System.Linq;
using System.Web.Mvc;
using MvcApplication1.Helper;

namespace MvcApplication1.Controllers
{
    public class HomeController : Controller
    {
        private FileHelper helper;

        public HomeController()
        {
            helper = new FileHelper();
        }

        public ActionResult Index()
        {
            var files = helper.GetFiles();
            return View(files);
        }

        public FileResult DownloadFile(string id)
        {
            var fId = Convert.ToInt32(id);
            var files = helper.GetFiles();
            string fileName = (from f in files
                where f.Id == fId
                select f.Path).FirstOrDefault();
            string contentType = "application/pdf";
            return File(fileName, contentType, "Report.pdf");
        }
    }
}

Home/Index.cshtml中：

@model IEnumerable<MvcApplication1.Models.FileForDownload>

@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<table>
    @foreach (var item in Model)
    {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.Id)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Name)
            </td>
            <td>
                @Html.ActionLink("下载", "DownloadFile", new { id = item.Id })
            </td>
        </tr>
        
    }
</table>

参考资料：
Download Files in ASP.NET MVC 3 using Controller Action