el-upload无法获取fileList

Question

在onchange事件时输出fileList, 结果为undefined.

问题相关代码，请勿粘贴截图

<template>
  <el-upload
    action="https://jsonplaceholder.typicode.com/posts/"
    :show-file-list="true"
    :on-change="onchange()"
    :before-upload="onchange()"
    :auto-upload="false"
    ref="upload"
    :file-list="data.fileList"
  >
    <template v-slot:trigger>
      <el-button type="primary">选择文件</el-button>
    </template>
    <el-button class="ml-3" type="success" @click="submit"> 上传 </el-button>
    <template v-slot:tip>
      <div class="el-upload__tip text-red">
        limit 1 file, new file will cover the old file
      </div>
    </template>
  </el-upload>
</template>

import { ref, reactive } from "vue";
const upload = ref(null);

export default {
  setup() {
    let data = reactive({
      fileList: [],
    });

    const onchange = (file, fileList) => {
      console.log(file);
      console.log(fileList);
    };

    return {
      data,
      onchange,
      upload
    };
  },
};

运行结果及报错内容

感谢