vue中v-for和v-if一起使用之使用compute的示例代码

目录

• 版本
• 目标效果
• 说明
• 解决方法
• 核心代码片段
• Car.vue

版本

vue 2.9.6
element-ui: 2.15.6

目标效果

说明

在 vue 2.x 中，在一个元素上同时使用 v-if 和 v-for 时，v-for 会优先作用

解决方法

选择性地渲染列表，例如根据某个特定属性（category ）来决定不同展示渲染，使用计算属性computed使用template占位，将循环放在template中，v-if作用于元素，此方法script中不用定义computed方法，见 https://www.jb51.net/article/247179.htm

核心代码片段

# html
...
<el-divider content-position="left">奥迪</el-divider>
<el-link type="primary" target="_blank" v-for="(item, index) in links0" :key="index" :href="item.url" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >
  <el-button type="primary">{{item.name}}</el-button>
</el-link>
...
# script
...
computed: {
  links0: function() {
    return this.links.filter((item) => {
      return item.category === 0
    })
  },
  links1: function() {
    return this.links.filter((item) => {
      return item.category === 1
    })
  },
  links2: function() {
    return this.links.filter((item) => {
      return item.category === 2
    })
  }
},

Car.vue

<template>
  <div>
    <el-row>
      <el-col :span="24">
        <el-form :inline="true" class="user-search">
          <el-form-item>
            <el-button size="small" type="primary" icon="el-icon-plus" @click="handleEdit()" plain>添加链接</el-button>
          </el-form-item>
        </el-form>
        <div >
          <el-divider content-position="left">奥迪</el-divider>
          <el-link type="primary" target="_blank" v-for="(item, index) in links0" :key="index" :href="item.url" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >
            <el-button type="primary">{{item.name}}</el-button>
          </el-link>
          <el-divider content-position="left">奔驰</el-divider>
          <el-link type="primary" target="_blank" v-for="(item, index) in links1" :key="index" :href="item.url" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >
            <el-button type="primary">{{item.name}}</el-button>
          </el-link>
          <el-divider content-position="left">宝马</el-divider>
          <el-link type="primary" target="_blank" v-for="(item, index) in links2" :key="index" :href="item.url" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >
            <el-button type="primary">{{item.name}}</el-button>
          </el-link>
        </div>
        <!-- 添加界面 -->
        <el-dialog :title="title" :visible.sync="editFormVisible" width="30%" @click="closeDialog">
          <el-form label-width="120px" :model="editForm" :rules="rules" ref="editForm">
          <el-form-item label="链接名称" prop="name">
            <el-input size="small" v-model="editForm.name" auto-complete="off" placeholder="请输入链接名称"></el-input>
          </el-form-item>
          <el-form-item label="链接地址" prop="url">
            <el-input size="small" v-model="editForm.url" auto-complete="off" placeholder="请输入链接地址"></el-input>
          </el-form-item>
          </el-form>
          <div slot="footer" class="dialog-footer">
          <el-button size="small" @click="closeDialog">取消</el-button>
          <el-button size="small" type="primary" :loading="loading" class="title" @click="submitForm('editForm')">保存</el-button>
          </div>
        </el-dialog>
      </el-col>
    </el-row>
  </div>
</template>
<script>
import { getLink, saveLink } from '../../api/userMG'
export default {
  data() {
    return {
      links: [],
      loading: false, //显示加载
      editFormVisible: false, //控制添加页面显示与隐藏
      title: '添加链接',
      editForm: {
        name: '',
        url: ''
      },
      // rules表单验证
      rules: {
        name: [{ required: true, message: '请输入链接名称', trigger: 'blur' }],
        url: [{ required: true, message: '请输入链接地址', trigger: 'blur' }]
      },
    }
  },
  computed: {
    // 通过根据category属性来不同显示
    links0: function() {
      return this.links.filter((item) => {
        return item.category === 0
      })
    },
    links1: function() {
      return this.links.filter((item) => {
        return item.category === 1
      })
    },
    links2: function() {
      return this.links.filter((item) => {
        return item.category === 2
      })
    }
  },
  created() {
    // 获取链接
   this.getdata()
  },
  // 这下面的方法只有被调用才会被执行
  methods: {
    // 获取链接
    getdata() {
      this.loading = true
      getLink().then((response) => {
        this.loading = false
        console.log(response.data)
        this.links = response.data
      }).catch(error => {
        console.log(error)
      })
    },
    // 添加页面方法
    handleEdit: function() {
      this.editFormVisible = true
      this.title = '添加链接',
      this.editForm.name = '',
      this.editForm.url = ''
    },
    // 添加保存页面方法
    submitForm(editData) {
      this.$refs[editData].validate(valid => {
        if (valid) {
          saveLink(this.editForm).then(response => {
            this.editFormVisible = false
            this.loading = false
            // if (response.success)
            this.getdata()
            this.$message({
              type: 'success',
              message: '链接添加成功'
            })
          }).catch(error => {
            this.editFormVisible = false
            this.loading = false
            // console.log(error.response.data['url'][0])
            // console.log(error.response.status)
            // this.$message.error('链接添加失败，请稍后再试')
            if (error.response.status == 400 ) {
              this.$message.error(error.response.data['url'][0]+'如: http://xxx 或 https://xxx')
            }else {
              this.$message.error('链接添加失败，请稍后再试')
            }
          })
        }
      })
    },
    // 关闭添加链接窗口
    closeDialog() {
      this.editFormVisible = false
    }
  }
}
</script>
<style>
  /* .el-row {
    margin-top: 10px;
  } */
  .el-link {
    margin-right: 5px;
  }
</style>

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