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-upload
                    class="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"
                  >
                    <img
                      v-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-upload
                    class="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"
                  >
                    <img
                      v-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>