VUE中,el-select选择器多选下拉框实现全选功能和取消全选

Select 选择器之elementUI版——https://element.eleme.cn/#/zh-CN/component/select

Select 选择器之Ant Design of Vue版——https://www.antdv.com/components/select-cn/

场景

elementUI的下拉框支持多选，但是不支持全选，但需求就要这个功能

解决思路

方法一：下拉项增加一个【全选】

应该有以下几种情况：

• 下拉选项全都勾选时，【全选】自动勾选；

• 下拉选项部分勾选时，点击【全选】后，所有下拉项全部勾选；

• 下拉选项全都未勾选时，点击【全选】后，所有下拉选项全部勾选；

• 下拉选项和【全选】都选上的时候，不勾选任意下拉选项，【全选】按钮就不勾选了；

实例1

html

<template>
    <el-select multiple collapse-tags v-model='selectedArray' @change='changeSelect' @remove-tag='removeTag' placeholder='请选择'>
        <el-option label='全选' value='全选' @click.native='selectAll'></el-option>
        <el-option v-for='(item, index) in options' :key='index' :label='item.name' :value='item.name'></el-option>
     </el-select>
</template>

js

export default {
  data() {
    return {
      selectedArray: [],
      options: [
        { name: '一一', label: 'one' },
        { name: '二二', label: 'tow' },
        { name: '三三', label: 'three' },
        { name: '四四', label: 'four' },
        { name: '五五', label: 'five' }
      ]
    }
  },
  methods: {
    selectAll() {
      if (this.selectedArray.length < this.options.length) {
        this.selectedArray = []
        this.options.map((item) => {
          this.selectedArray.push(item.name)
        })
        this.selectedArray.unshift('全选')
      } else {
        this.selectedArray = []
      }
    },
    changeSelect(val) {
      if (!val.includes('全选') && val.length === this.options.length) {
        this.selectedArray.unshift('全选')
      } else if (val.includes('全选') && (val.length - 1) < this.options.length) {
        this.selectedArray = this.selectedArray.filter((item) => {
          return item !== '全选'
        })
      }
    },
    removeTag(val) {
      if (val === '全选') {
        this.selectedArray = []
      }
    }
  }
}

效果图

方法二：直接添加一个【全选】复选框

实现的功能跟方法一是一样的

html

<template>
  <el-select multiple collapse-tags v-model='selectedArray' @change='changeSelect' placeholder='请选择'>
    <el-checkbox v-model="checked" @change='selectAll'>全选</el-checkbox>
    <el-option v-for='(item, index) in options' :key='index' :label='item.name' :value='item.name'></el-option>
  </el-select>
</template>

js

export default {
  data() {
    return {
      checked: false,
      selectedArray: [],
      options: [
        { name: '一一', label: 'one' },
        { name: '二二', label: 'tow' },
        { name: '三三', label: 'three' },
        { name: '四四', label: 'four' },
        { name: '五五', label: 'five' }
      ]
    }
  },
  methods: {
    selectAll() {
      this.selectedArray = []
      if (this.checked) {
        this.options.map((item) => {
          this.selectedArray.push(item.name)
        })
      } else {
        this.selectedArray = []
      }
    },
    changeSelect(val) {
      if (val.length === this.options.length) {
        this.checked = true
      } else {
        this.checked = false
      }
    }
  }
}

css

.el-checkbox {
    text-align: right;
    width: 100%;
    padding-right: 10px;
}

效果图