element ui文件上传方法中需要传额外参数

由于文件上传dom是通过循环列表渲染的，在文件上传的时候除了file默认的参数外，还需要访问到循环项item参数，那就这样子传递。

:http-request="(file) => {return httpRequestLT(file, item);}
"

完整代码如下

  <div class="listcon_wrap" v-for="(item, index) in navList" :key="index"><div class="left_wrap"><span class="sortIndx">{{ index }}</span><div class="upload_box"><el-uploadclass="upload-demo"ref="upload"action="#":show-file-list="false":http-request="(file) => {return httpRequest1(file, item);}":on-change="changeData":on-success="handleSuccess"style="display: inline-block"><imgv-if="item.lightBg":src="'data:image/jpg;base64,' + item.lightBg"class="avatar"/><i v-else class="el-icon-plus avatar-uploader-icon"></i></el-upload></div><div class="upload_box"><el-uploadclass="upload-demo"ref="upload"action="#":show-file-list="false":http-request="(file) => {return httpRequest2(file, item);}":on-change="changeData":on-success="handleSuccess"style="display: inline-block"><imgv-if="item.darkBg":src="'data:image/jpg;base64,' + item.darkBg"class="avatar"/><i v-else class="el-icon-plus avatar-uploader-icon"></i></el-upload></div></div></div>