一、自动上传和手动上传

上传图片分两种，自动上传和手动上传，效果区别：

自动上传：选择图片后立刻调接口上传图片

手动上传：选择图片后只显示图片，自定义何时上传，可以定义点击确定事件里表单验证成功后上传图片

区别：自动上传会造成很多脏数据，手动上传等到上传时才校验图片是否合规

二、手动上传

表单中使用el-upload手动上传图片，组件选择的是照片墙

<template>
    <el-form
      ref="cardFormRef"
      :model="cardForm"
      :rules="rules"
      label-width="120px"
      class="demo-cardForm"
      status-icon
    >
    <el-form-item label="轮播图" prop="photo">
        <el-upload
          ref="uploadRef"
          :class="{ iconVis: fileList.length }"
          :action="url" //上传接口
          v-model:file-list="fileList"
          :limit="1" //限制上传一张
          list-type="picture-card"  //照片墙
          :before-upload="beforeUpload"  //上传前
          :on-success="handleAvatarSuccess"  //上传成功
          :headers="headers"
          :auto-upload="false"  //手动上传
        >
          <el-icon class="avatar-uploader-icon"><Plus /></el-icon>
        </el-upload>
      </el-form-item>
  </el-form>
</template>

var fileList = ref([]);
var uploadUrl = ref(false); //存图片成功返回的url
const headers = ref({ Authorization: "Bearer " + getToken() });
var url =import.meta.env.VITE_APP_BASE_API + "接口";

var rules = computed(() => ({  //表单校验规则
  photo: [
    {
      required: true,
      message: "请上传图片",
      trigger: "blur",
    },
  ]
}));

var beforeUpload = (file) => {
  console.log("上传前");
  const isJPG =
    file.type === "image/jpeg" ||
    file.type === "image/png" ||
    file.type === "image/jpg";
  const isLt2M = file.size / 1024 / 1024 < 2;
  if (!isJPG) {
    proxy.$modal.msgError("上传图片只能是 JPG/PNG 格式!");
  }
  if (!isLt2M) {
    proxy.$modal.msgError("上传图片大小不能超过 2MB!");
  }
  isJPG && isLt2M ? (uploadUrl.value = true) : (uploadUrl.value = false);
  return isJPG && isLt2M;
};

function handleAvatarSuccess(res, file) {
  console.log("成功了！");
  let { url } = res.data;
  uploadUrl.value = url;
  sumbitForm(); //表单提交接口，传uploadUrl
}

var cardFormRef=ref(null);
var uploadRef=ref(null);
var sumbit = () => {  //点击确定按钮，进行表单校验，校验成功上传图片
  cardFormRef.value.validate((val) => {
    if (val) {
      console.log("上传图片");
     uploadRef.value.submit();
    }
  });
};

点击确定sumbit,表单校验成功 => beforeUpload检查图片符合规格 => handleAvatarSuccess图片上传成功 =>sumbitForm提交表单，包含图片上传成功返回的url