element 使用多个upload组件，绑定元素_使用多个el-upload组件

<el-form-item :label="item.tip" :prop="item.tip" v-if="item.htmlType==1">
        <el-upload
          class="upload-demo"
          action="https://jsonplaceholder.typicode.com/posts/"
          :before-upload="function (file){return beforeUpload(file,item.field_name)}"
          :on-remove="handleRemove"
          :file-list="ruleForm[item.field_name]"
          list-type="picture"
        >
          <el-button size="small" type="primary">点击上传</el-button>
          <div slot="tip" class="el-upload__tip">只能上传jpg/png文件</div>
        </el-upload>
      </el-form-item>