antd select 多选限制个数的实现代码

<template>
       <a-select
              v-model="college"
              mode="multiple"
              :maxTagCount="2"
              autocomplete="off"
              style="width: 252px;margin-top:10px;margin-right: 28px"
              :getPopupContainer="triggerNode => triggerNode.parentNode"
            >
              <a-select-option
                v-for="item in collegeList"
                :key="item.id"
                :value="item.name"
                :disabled="college.length >= 5 && college.findIndex(o => o === item.name) === -1"
              >
                {{ item.name }}
              </a-select-option>
          </a-select>
</template>
 <script>  
	 data() {
	    return { 
	      collegeList: [],
	      college: []
	    }
	  },
 </script>  

[
  {
    "city": "北京市",
    "code": "4111010001",
    "createBy": null,
    "createTime": null,
    "department": "教育部",
    "id": 1,
    "level": "本科",
    "name": "北京大学",
    "updateBy": null,
    "updateTime": null
  },
  {
    "city": "北京市",
    "code": "4111010002",
    "createBy": null,
    "createTime": null,
    "department": "教育部",
    "id": 2,
    "level": "本科",
    "name": "中国人民大学",
    "updateBy": null,
    "updateTime": null
  },
  {
    "city": "北京市",
    "code": "4111010003",
    "createBy": null,
    "createTime": null,
    "department": "教育部",
    "id": 3,
    "level": "本科",
    "name": "清华大学",
    "updateBy": null,
    "updateTime": null
  }
]

		<a-select
              v-model="safeGroup"
              mode="multiple"
              placeholder="请选择安全组"
              class="long-input"
              :getPopupContainer="triggerNode => triggerNode.parentNode"
              @change="handleSafeChange"
            >
              <a-select-option
                v-for="item in SafeGroupList"
                :key="item.safeGroupId"
                :value="JSON.stringify(item)"
                :disabled="
                  safeGroup.length >= 5 &&
                  safeGroup.findIndex(o => JSON.parse(o).safeGroupId === item.safeGroupId) === -1
                "
              >
                <ellipsis :length="20"> {{ item.safeGroupName }}</ellipsis>
              </a-select-option>
             
            </a-select>

handleSafeChange(e) {
    if (e) {
      this.dispalySafe = false
      this.safeGroup = e
      const arr1 = e.map(x => {
        return JSON.parse(x)
      })
      const arr2 = e.map(x => {
        return JSON.parse(x).safeGroupId
      })
      this.$emit('handleSafeChange', arr2, arr1)
    }
  },

changeValues = (rule ,value , callback)=> {

const { setFieldsValue } = this.props.form ;

let newArr ;

if (value.length > 3){

newArr = [].concat(value.slice(0,2), value.slice(-1) ) ;

setFieldsValue({

"languages" : newArr ,

})

callback(‘最多选择三种语言‘)

} else {

newArr = value ;

callback()

}

}

{getFieldDecorator(‘languages‘, {

rules:[{required: true,message : ‘请选择三种语言‘,

validator : changeValues

}],

validateTrigger : ‘onChange‘,

})(

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)}