vue2+element-ui转化为Vue3+element plus
后台管理系统：增删查改
vue2页面：

<template>
  <div class="app-container">
    <div>
      <el-form
        :model="queryParams"
        ref="queryForm"
        size="small"
        :inline="true"
        class="tabel-form"
        label-width="80px"
      >
        <el-form-item label="影片分类">
          <el-input
            v-model="queryParams.categoryName"
            placeholder="请输入影片分类"
            clearable
            style="width: 180px;margin-right:20px;"
            @keyup.enter.native="handleQuery"
          />
        </el-form-item>
        <el-form-item>
          <el-button type="primary" icon="el-icon-search" size="mini" @click="handleQuery">搜 索</el-button>
          <el-button icon="el-icon-refresh" size="mini" @click="resetQuery">重 置</el-button>
        </el-form-item>
      </el-form>
      <el-button
        size="mini"
        type="success"
        plain
        icon="el-icon-plus"
        @click="addFilmType"
        style="margin-bottom:10px"
      >新增</el-button>
    </div>
    <el-table v-loading="loading" :data="dataList">
      <el-table-column
        label="序号"
        align="center"
        type="index"
        width="140"
        :show-overflow-tooltip="true"
      />
      <el-table-column
        label="分类名称"
        align="center"
        prop="categoryName"
        width="140"
        :show-overflow-tooltip="true"
      />
      <el-table-column
        label="首页最多显示个数"
        align="center"
        prop="showQuantity"
        width="140"
        :show-overflow-tooltip="true"
      />
      <el-table-column label="操作" align="center" class-name="small-padding fixed-width" width="200">
        <template slot-scope="scope">
          <div>
            <el-button
              size="mini"
              type="text"
              icon="el-icon-edit"
              @click="editFilmTypeName(scope.row)"
            >编辑</el-button>
            <el-button
              size="mini"
              type="text"
              icon="el-icon-delete"
              @click="deleteFilmTypeName(scope.row)"
            >删除</el-button>
          </div>
        </template>
      </el-table-column>
    </el-table>
    <pagination
      v-show="total>0"
      :total="total"
      :page.sync="queryParams.pageNum"
      :limit.sync="queryParams.pageSize"
      @pagination="getList"
    />
    <!-- 新增/编辑影片类型 -->
    <el-dialog :title="title" :visible.sync="open" width="500px" append-to-body @close="cancel">
      <el-form ref="form" :model="form" :rules="rules">
        <el-form-item label="分类名称" prop="categoryName">
          <el-input v-model="form.categoryName" placeholder="请输入分类名称"></el-input>
        </el-form-item>
        <el-form-item label="首页最多显示个数" prop="showQuantity">
          <el-input v-model="form.showQuantity" type="number" :min="0" placeholder="请输入个数"></el-input>
        </el-form-item>
      </el-form>
      <div slot="footer" class="dialog-footer">
        <el-button type="primary" @click="submitForm2">确定</el-button>
        <el-button @click="cancel">取消</el-button>
      </div>
    </el-dialog>
  </div>
</template>

<script>
import {
  sysVideoCategoryGetPage,
  sysVideoCategoryEdit,
  sysVideoCategoryDelete
} from '@/api/filmManagement/filmList'
import { convertTimestamp } from "@/utils/yun"

export default {
  name: 'Task',
  dicts: ['audit_type'],
  data () {
    return {
      // 遮罩层
      loading: false,
      // 总条数
      total: 0,
      // 店铺带货任务表格数据
      dataList: [],
      // 弹出层标题
      title: '',
      // 是否显示弹出层
      open: false,
      // 查询参数
      queryParams: {
        categoryName: "",
        pageNum: 1,
        pageSize: 10
      },
      rules: {
        categoryName: [
          { required: true, message: '分类名称不能为空', trigger: 'blur' }
        ],
        showQuantity: [
          { required: true, message: '个数不能为空', trigger: 'blur' }
        ],
      },
      form: {
        categoryName: null,
        showQuantity: null
      },
    }
  },
  created () {
    this.getList()
  },
  methods: {
    convertTimestamp,
    /** 查询直播间用户等级 */
    getList () {
      this.loading = true
      sysVideoCategoryGetPage(this.queryParams).then((res) => {
        this.dataList = res.data.records
        this.total = res.data.total
        this.loading = false
      }).catch(err => {
        this.loading = false
      })
    },
    /** 搜索按钮操作 */
    handleQuery () {
      this.queryParams.pageNum = 1
      this.getList()
    },
    /** 重置按钮操作 */
    resetQuery () {
      this.queryParams = {
        categoryName: null,
        pageNum: 1,
        pageSize: 10
      }
      this.handleQuery()
    },
    // 新增
    addFilmType () {
      this.open = true
      this.title = '新增影片类型'

    },
    // 编辑
    editFilmTypeName (row) {
      this.form = { ...row }
      console.log(this.form)
      this.open = true
      this.title = '编辑影片类型'

    },
    deleteFilmType (row) {
      sysVideoCategoryDelete(row.id).then((res) => {
        this.dataList = res.data.records
        this.total = res.data.total
        this.loading = false
      }).catch(err => {
        this.loading = false
      })
    },
    // 删除
    deleteFilmTypeName (row) {
      this.$modal.confirm('是否确认删除该影片分类？').then(function () {
        return sysVideoCategoryDelete([row.id])
      }).then(() => {
        this.getList()
        this.$modal.msgSuccess('删除成功')
      }).catch(() => {
      })
    },
    submitForm2 () {
      this.$refs['form'].validate(valid => {
        if (valid) {
          sysVideoCategoryEdit(this.form).then((res) => {
            this.open = false
            this.getList()
          }).catch(err => {
            this.open = false
          })
        }
      })
    },
    cancel () {
      this.open = false
      this.form = {
        categoryName: null,
        showQuantity: null
      }
    },
  }
}
</script>
<style lang="scss" scoped>
.details-row {
  line-height: 34px;
}
.product-item {
  padding-right: 10px;
}
</style>

vue3页面：

<template>
  <div class="app-container">
    <div>
      <el-form
        :model="queryParams"
        ref="queryForm"
        :inline="true"
        class="tabel-form"
        label-width="80px"
      >
        <el-form-item label="影片分类">
          <el-input
            v-model="queryParams.categoryName"
            placeholder="请输入影片分类"
            clearable
            style="width: 180px;margin-right:20px;"
            @keyup.enter.native="handleQuery"
          />
        </el-form-item>
        <el-form-item>
          <el-button type="primary" icon="Search" @click="handleQuery">搜 索</el-button>
          <el-button icon="Refresh" @click="resetQuery">重 置</el-button>
          <el-button type="success" icon="Plus" @click="addFilmType" plain>新 增</el-button>
        </el-form-item>
      </el-form>
    </div>
    <el-table v-loading="loading" :data="dataList" border>
      <el-table-column
        label="序号"
        align="center"
        type="index"
        width="240"
        :show-overflow-tooltip="true"
      />
      <el-table-column
        label="分类名称"
        align="center"
        prop="categoryName"
        width="240"
        :show-overflow-tooltip="true"
      />
      <el-table-column
        label="首页最多显示个数"
        align="center"
        prop="showQuantity"
        width="240"
        :show-overflow-tooltip="true"
      />
      <el-table-column label="操作" align="left">
        <template #default="scope">
          <div>
            <el-button
              size="default"
              link
              type="primary"
              icon="el-icon-edit"
              @click="editFilmTypeName(scope.row)"
            >编辑</el-button>
            <el-button
              size="default"
              link
              type="primary"
              icon="el-icon-delete"
              @click="deleteFilmTypeName(scope.row)"
            >删除</el-button>
          </div>
        </template>
      </el-table-column>
    </el-table>
    <pagination
      v-show="total > 0"
      :total="total"
      v-model:page="queryParams.pageNum"
      v-model:limit="queryParams.pageSize"
      @pagination="getList"
    />
    <!-- 新增/编辑影片类型 -->
    <el-dialog :title="title" v-model="open" width="700px" append-to-body @close="cancel">
      <el-form :model="form" :rules="rules" label-width="140px" ref="formRef">
        <el-form-item label="分类名称" prop="categoryName">
          <el-input v-model="form.categoryName" placeholder="请输入分类名称"></el-input>
        </el-form-item>
        <el-form-item label="首页最多显示个数" prop="showQuantity">
          <el-input v-model="form.showQuantity" type="number" :min="0" placeholder="请输入个数"></el-input>
        </el-form-item>
      </el-form>
      <template #footer>
        <div class="dialog-footer">
          <el-button type="primary" @click="submitForm2(formRef)">确定</el-button>
          <el-button @click="cancel">取消</el-button>
        </div>
      </template>
    </el-dialog>
  </div>
</template>

<script setup>
import {
  sysVideoCategoryGetPage,
  sysVideoCategoryEdit,
  sysVideoCategoryDelete
} from '@/api/filmManagement/filmList'
import { ref, getCurrentInstance, reactive } from 'vue'
import {
  ElMessage,
  ElMessageBox
} from 'element-plus'
const { proxy } = getCurrentInstance()
const loading = ref(false)
const total = ref(0)
const dataList = ref([])
const open = ref(false)
const title = ref('')
const queryParams = reactive({
  categoryName: "",
  pageNum: 1,
  pageSize: 10
})


const formRef = ref(null)
const rules = reactive({
  categoryName: [
    { required: true, message: '分类名称不能为空', trigger: 'blur' }
  ],
  showQuantity: [
    { required: true, message: '个数不能为空', trigger: 'blur' }
  ],
})
const form = ref({
  categoryName: 12,
  showQuantity: 0
})

function getList () {
  loading.value = true
  console.log(queryParams)
  sysVideoCategoryGetPage(queryParams).then((res) => {
    console.log(res)
    dataList.value = res.records
    total.value = Number(res.total)
    loading.value = false
  }).catch(err => {
    loading.value = false
  })
}

function handleQuery () {
  queryParams.pageNum = 1
  getList()
}

function resetQuery () {
  queryParams.categoryName = null
  queryParams.pageNum = 1
  queryParams.pageSize = 10
  handleQuery()
}

function addFilmType () {
  form.value = {
    categoryName: null,
    showQuantity: null
  }
  open.value = true
  title.value = '新增影片类型'
}

function editFilmTypeName (row) {
  form.value = { ...row }
  open.value = true
  title.value = '编辑影片类型'
}

function deleteFilmType (row) {
  sysVideoCategoryDelete(row.id).then((res) => {
    dataList.value = res.data.records
    total.value = res.data.total
    loading.value = false
  }).catch(err => {
    loading.value = false
  })
}

function deleteFilmTypeName (row) {
  ElMessageBox.confirm('是否确认删除' + ' "' + row.categoryName + '" ' + '影片分类？').then(function () {
    return sysVideoCategoryDelete([row.id])
  }).then(() => {
    getList()
    ElMessage({
      type: 'success',
      message: '删除成功',
    })
  }).catch(() => {
    ElMessage({
      type: 'info',
      message: '删除取消',
    })
  })
}

function submitForm2 () {
  if (!formRef.value) return
  formRef.value.validate(valid => {
    if (valid) {
      sysVideoCategoryEdit(form.value).then((res) => {
        open.value = false
        if (title.value = '新增影片类型') {
          ElMessage({
            type: 'success',
            message: '新增成功',
          })
        } else {
          ElMessage({
            type: 'success',
            message: '修改成功',
          })
        }
        getList()
      }).catch(err => {
        open.value = false
      })
    }
  })
}

function cancel () {
  open.value = false
  form.value = {
    categoryName: null,
    showQuantity: null
  }
}
getList()
</script>

html部分大体没有任何改变，js方面
1.script标签里面添加setup 语法糖
2.vue2 的data，都需要在vue3里面声明，
const loading = ref(false)
使用的时候：loading.value
3.vue2里面的方法，必须声明在methods,vue3里面，方法和变量都放在一个区域
vue3里面没有this，方法直接使用

element-ui和element plus大体相同，但是有些属性的使用发生了变化
1.按钮的图标

2.表格的自定义列模板

3.模态框的现实与隐藏

4.分页的当前页数和每页默认的条目个数
后面遇到变化再补充