MVC文件上传07-使用客户端jQuery-File-Upload插件和服务端Backload组件裁剪上传图片

本篇通过在配置文件中设置，对上传图片修剪后保存到指定文件夹。

相关兄弟篇：

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文件上传02-使用HttpPostedFileBase上传多个文件  
MVC文件上传03-使用Request.Files上传多个文件
MVC文件上传04-使用客户端jQuery-File-Upload插件和服务端Backload组件实现多文件异步上传  
MVC文件上传05-使用客户端jQuery-File-Upload插件和服务端Backload组件自定义上传文件夹 
MVC文件上传06-使用客户端jQuery-File-Upload插件和服务端Backload组件自定义控制器上传多个文件 

□ 思路

1、自定义控制器继承Backload的默认控制器BackloadController
2、自定义一个jQuery File Upload初始化js文件，使用自定义控制器的方法
3、在视图页面调用自定义jQuery File Upload初始化js文件

□ 安装Backload组件和jQuery File Upload插件

→在"程序包管理器控制台"输入：Install-Package Backload
1

→在"程序包管理器控制台"输入： Install-Package JQuery_File_Upload_Plugin
2

□ 自定义BaseController继承BackloadController

   1:  using System.Web.Mvc;
   2:   
   3:  namespace MvcApplication7.Controllers
   4:  {
   5:      public class BaseController : BackloadController
   6:      {
   7:          //public ActionResult Index()
   8:          //{
   9:          //    return View();
  10:          //}
  11:   
  12:          public async Task<ActionResult> FileHandler()
  13:          {
  14:              ActionResult result = await base.HandleRequestAsync();
  15:              return result;
  16:          }
  17:      }
  18:  }

□ 自定义HomeController继承BaseController

   1:  using System.Web.Mvc;
   2:  namespace MvcApplication7.Controllers
   3:  {
   4:      public class HomeController : BaseController
   5:      {
   6:          public ActionResult Index()
   7:          {
   8:              return View();
   9:          }
  10:      }
  11:  }

□ 自定义用于初始化jQuery File Upload的js文件main.js

其中，还限制了上传文件的格式。

   1:  $(function () {
   2:      'use strict';
   3:   
   4:      var url = '/Base/FileHandler';
   5:      // Initialize the jQuery File Upload widget:
   6:      $('#fileupload').fileupload({
   7:          // Uncomment the following to send cross-domain cookies:
   8:          //xhrFields: {withCredentials: true},
   9:          url: url,
  10:          acceptFileTypes: /(jpg)|(jpeg)|(png)|(gif)$/i // Allowed file types
  11:      });
  12:   
  13:      // Enable iframe cross-domain access via redirect option:
  14:      $('#fileupload').fileupload(
  15:          'option',
  16:          'redirect',
  17:          window.location.href.replace(
  18:              //[^/]*$/,
  19:              '/cors/result.html?%s'
  20:          )
  21:      );
  22:   
  23:      // Load existing files by an initial ajax request to the server after page loads up
  24:      // This is done by a simple jQuery ajax call, not by the FIle Upload plugin.,
  25:      // but the results are passed to the plugin with the help of the context parameter: 
  26:      // context: $('#fileupload')[0] and the $(this)... call in the done handler. 
  27:      // With ajax.context you can pass a JQuery object to the event handler and use "this".
  28:      $('#fileupload').addClass('fileupload-processing');
  29:      $.ajax({
  30:          // Uncomment the following to send cross-domain cookies:
  31:          //xhrFields: {withCredentials: true},
  32:          url: url,
  33:          dataType: 'json',
  34:          context: $('#fileupload')[0]
  35:      }).always(function () {
  36:          $(this).removeClass('fileupload-processing');
  37:      }).done(function (result) {
  38:          $(this).fileupload('option', 'done')
  39:              .call(this, null, { result: result });
  40:      });
  41:  });
  42:   
  43:  $("document").ready(function () {
  44:      $('#fileupload')
  45:          .bind('fileuploaddestroy', function (e, data) {
  46:              // Event handler example. Do something if you need after file has been deleted on the server. 
  47:              // (Refer to the client side documentatio).
  48:          });
  49:   
  50:  });
  51:   

□ _Layout.cshtml布局视图

   1:  <!DOCTYPE html>
   2:  <html>
   3:  <head>
   4:      <meta charset="utf-8" />
   5:      <meta name="viewport" content="width=device-width" />
   6:      <title>@ViewBag.Title</title>
   7:      @Styles.Render("~/Content/css")
   8:      @Styles.Render("~/Content/themes/base/css")
   9:      @Styles.Render("~/bundles/fileupload/bootstrap/BasicPlusUI/css")
  10:      @Scripts.Render("~/bundles/modernizr")
  11:  </head>
  12:  <body>
  13:      @RenderBody()
  14:   
  15:      @Scripts.Render("~/bundles/jquery")
  16:      @Scripts.Render("~/bundles/jqueryui")
  17:      @Scripts.Render("~/bundles/fileupload/bootstrap/BasicPlusUI/js")
  18:      @RenderSection("scripts", required: false)
  19:  </body>
  20:  </html>
  21:   

□ Home/Index.cshtml视图

展开


□ web.config

   1:  <configuration>
   2:    <configSections>
   3:        ...
   4:        <section name="backload" type="Backload.Configuration.BackloadSection, Backload, Version=1.9.3.1, Culture=neutral, PublicKeyToken=02eaf42ab375d363" requirePermission="false" /></configSections>
   5:    <configSections>
   6:    <backload configSource="Web.backload.config" />
   7:  </configuration>


 
□ 所有Backload的配置放在Web.backload.config中

   1:  <?xml version="1.0"?>
   2:   
   3:  <backload xsi:noNamespaceSchemaLocation="Web.Backload.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:name="urn:backload-schema" thumbsUrlPattern="{Backload}">
   4:   
   5:    <images width="200" height="200" dpi="96" resizeMode="ratio" />
   6:    <thumbnails path="" width="60" height="60" canvasColor="#00000000" resizeMode="place" imageType="image/png" />
   7:    <fileSystem filesRoot="~/Upload" />
   8:    <cacheManager lastModified="true" etag="true"/>
   9:  </backload>

● width和height实际上设置的是画布Canvas的大小。
● 没有resizeMode属性：保持上传图片的大小不变
● resizeMode="ration": 当图片的宽度大于画布的宽度，图片的宽度修剪为画布的宽度，图片的高度等比例缩放，画布背景不显示
● resizeMode="fit": 当图片的宽度大于画布的宽度，图片的宽度修剪为画布的宽度，图片的高度等比例缩放，画布背景显示
● resizeMode="place": 当图片的宽度小于画布的宽度，图片的宽度修剪为画布的宽度，图片的高度等比例缩放，画布背景显示
● resizeMode="crop": 图片的宽度或高度充满画布的宽度或高度，空白的画布区域裁剪掉。

□ 结果

上传界面：
3

 

由于设置了path=""，所以没有了缩略图：

由于设置了resizeMode="ratio"，上传图片宽度不变，高度按比例缩小：
4

□ 设置文件夹带缩略图文件夹path="_thumb"

   1:  <backload xsi:noNamespaceSchemaLocation="Web.Backload.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:name="urn:backload-schema" thumbsUrlPattern="{Backload}">
   2:   
   3:    <images width="200" height="200" dpi="96" resizeMode="ratio" />
   4:    <thumbnails path="_thumb" width="60" height="60" canvasColor="#00000000" resizeMode="place" imageType="image/png" />
   5:    <fileSystem filesRoot="~/Upload" />
   6:    <cacheManager lastModified="true" etag="true"/>
   7:  </backload>


增加一个图片：
5

 

由于设置了path="_thumb"，所以有了缩略图文件夹：
6

 

由于缩略图设置了resizeMode="place"，图片宽度等于画布宽度，高度等比例缩放，显示背景：
7

 

由于在main.js中设置了acceptFileTypes: /(jpg)|(jpeg)|(png)|(gif)$/i，pdf格式不允许：
8

参考资料：
※ http://backload.org/ Backload官网
※ https://github.com/blackcity/Backload#examples Backload例子
※ http://nuget.org/packages/Backload/ nuget上的Backload

※ http://blueimp.github.io/jQuery-File-Upload/ jQuery File Upload官网
※ https://github.com/blueimp/jQuery-File-Upload/wiki  github上的jQuery File Upload介绍
※ https://github.com/blueimp/jQuery-File-Upload  github上的jQuery File Upload源码

※ https://www.nuget.org/packages/JQueryFileUpload_Demo_with_Backload/  下载jQuery File Upload结合Backload的MVC案例

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原文地址：https://www.cnblogs.com/darrenji/p/3620618.html