MVC文件上传02-使用HttpPostedFileBase上传多个文件

本篇体验上传多个文件。兄弟篇为:


MVC文件上传01-使用jquery异步上传并客户端验证类型和大小

       

  MVC最基本上传文件方式中的一个遗漏点

□ 前台视图部分

   1:  <% using(Html.BeginForm("FileUpload", "FileUpload", FormMethod.Post, new {enctype = "multipart/form-data"}) {)%>
   2:      <input name ="uploadFile" type="file" />
   3:      <input type="submit" value="Upload File" />
   4:  <%}%>

 

□ 控制器部分

   1:  [HttpMethod.Post]
   2:  public ActionResult FileUpload(HttpPostedFileBase uploadFile)
   3:  {
   4:      if(uploadFile.ContenctLength > 0)
   5:      {
   6:          //获得保存路径
   7:          string filePath = Path.Combine(HttpContext.Server.MapPath("../Uploads"), 
   8:                          Path.GetFileName(uploadFile.FileName));
   9:          uploadFile.SaveAs(filePath);
  10:      }
  11:      return View();
  12:  }

 

以上的问题是:当没有文件上传的时候,会报错。需要判断HttpPostedFileBase实例是否为null

   1:  [HttpMethod.Post]
   2:  public ActionResult FileUpload(HttpPostedFileBase uploadFile)
   3:  {
   4:    if(uploadFile != null)
   5:    {
   6:      if(uploadFile.ContenctLength > 0)
   7:      {
   8:          //获得保存路径
   9:          string filePath = Path.Combine(HttpContext.Server.MapPath("../Uploads"), 
  10:                          Path.GetFileName(uploadFile.FileName));
  11:          uploadFile.SaveAs(filePath);
  12:      }
  13:    }
  14:      return View();
  15:  }

 

  上传多个文件

□ 控制器

● 由于接收多个文件,所以控制器方法的参数变成了IEnumerable<HttpPostedFileBase> files
● 变量files与前台视图的name属性值对应
● 如果没有指定的文件夹,就创建一个文件夹

 

   1:  using System;
   2:  using System.Collections.Generic;
   3:  using System.IO;
   4:  using System.Linq;
   5:  using System.Web;
   6:  using System.Web.Mvc;
   7:   
   8:  namespace MvcApplication2.Controllers
   9:  {
  10:      public class HomeController : Controller
  11:      {
  12:          public ActionResult Index()
  13:          {
  14:              return View();
  15:          }
  16:   
  17:          public ActionResult MultiUpload(IEnumerable<HttpPostedFileBase> files)
  18:          {
  19:              string pathForSaving = Server.MapPath("~/Uploads");
  20:              if (this.CreateFolderIfNeeded(pathForSaving))
  21:              {
  22:                  foreach (var file in files)
  23:                  {
  24:                      if (file != null && file.ContentLength > 0)
  25:                      {
  26:                          var path = Path.Combine(pathForSaving, file.FileName);
  27:                          file.SaveAs(path);
  28:                      }
  29:                  }
  30:              }
  31:              
  32:              return RedirectToAction("Index");
  33:          }
  34:   
  35:          // 检查是否要创建上传文件夹
  36:          private bool CreateFolderIfNeeded(string path)
  37:          {
  38:              bool result = true;
  39:              if (!Directory.Exists(path))
  40:              {
  41:                  try
  42:                  {
  43:                      Directory.CreateDirectory(path);
  44:                  }
  45:                  catch (Exception)
  46:                  {
  47:                      //TODO:处理异常
  48:                      result = false;
  49:                  }
  50:              }
  51:              return result;
  52:          }
  53:      }
  54:  }
  55:   

□ Home/Index.cshtml视图

   1:  @{
   2:      ViewBag.Title = "Index";
   3:      Layout = "~/Views/Shared/_Layout.cshtml";
   4:  }
   5:   
   6:  @using (Html.BeginForm("MultiUpload", "Home", FormMethod.Post, new {enctype = "multipart/form-data"}))
   7:  {
   8:      <input type="file" name="files" id="file1" /><br/>
   9:      <input type="file" name="files" id="file2" /><br/>
  10:      <input type="file" name="files" id="file3" /><br/>
  11:      <input type="submit" value="同时上传多个文件" />
  12:  }

 

注意:name属性值与控制器方法参数对应。

□ 结果

选择上传2个文件:

1


上传成功后,自动创建了文件夹Uploads:

2


Uploads中只有2个文件:

3


□ 为什么使用HttpPostedFileBase而不是FormCollection来接收文件

public sealed class FormCollection : NameValueCollection, IValueProvider

可见,FormCollection是键值集合,键是string类型,值是string类型,而上传的文件类型不是string,所以不能用FormCollection作为参数来接收文件。

 

参考资料

ASP.NET MVC文件上传的基本操作

posted @ 2014-03-21 00:34  Darren Ji  阅读(6931)  评论(1编辑  收藏  举报

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