directive.ts

import { Directive, DirectiveBinding } from 'vue'

const loadMore: Directive = {
	beforeMount(el: any, binding: DirectiveBinding) {
		let arg = binding.arg as any
		if (!arg) return
		const selectDom = document.querySelector(`.${arg.name} .el-select-dropdown .el-select-dropdown__wrap`)
		function loadMores(this: any) {
			const isBase = this.scrollHeight - this.scrollTop <= this.clientHeight
			if (isBase) {
				binding.value && binding.value(arg)
			}
		}
		el.selectDomInfo = selectDom
		el.userLoadMore = loadMores
		selectDom?.addEventListener('scroll', loadMores)
	},
	beforeUnmount(el: any) {
		if (el.userLoadMore) {
			el.selectDomInfo.removeEventListener('scroll', el.userLoadMore)
			delete el.selectDomInfo
			delete el.userLoadMore
		}
	}
}
export default loadMore

main.ts

import { createApp } from 'vue'
import App from './App.vue'
import router from '/@/router'
import loadMore from './directive'
 
const app = createApp(App)
app.use(router).directive('loadMore', loadMore)

封装后组件：scrollSelect文件下Index.vue

<script setup lang="ts">
interface selectProps {
  modelValue: any; //选择赋值
  name: string; //一个父与子里面的下拉：不可重复
  methods: (data: any) => any; //接口方法
  label: any; //下拉中显示值
  multiple: boolean; //是否多选
  placeholder: string; //占位显示
  key: string; //Key源
  value: string; //value源
  disabled: boolean; //是否禁用
  change: Function | undefined; //下拉方法
}
const props = withDefaults(defineProps<selectProps>(), {
  modelValue: null,
  name: "select",
  label: null,
  multiple: false, //默认不可多选
  placeholder: "请选择",
  key: "ID", //默认
  value: "ID", //默认
  disabled: false, //默认不禁用
  change: () => {},
});
const emit = defineEmits(["update:modelValue"]);
const modelCpd = computed({
  get() {
    return props.modelValue;
  },
  set(value) {
    emit("update:modelValue", value);
  },
});

const reSelect = reactive({
  modelValue: props.modelValue,
  name: props.name,
  PageIndex: 0,
  PageSize: 10,
  finished: false,
  optionList: [] as any,
  methods: props.methods,
});

//加载数据
const loadMore = (Select: any) => {
  // 防抖处理
  setTimeout(async () => {
    if (Select.finished) return;
    Select.PageIndex += 1;
    var seacth = {
      name: Select.name,
      PageIndex: Select.PageIndex,
      PageSize: Select.PageSize,
    };
    console.log(seacth);
    let res = await Select.methods(seacth);
    if (res.Data && res.Data.length > 0) {
      Select.optionList = Select.optionList.concat(res.Data);
    }
    if (res.Total <= Select.optionList.length) {
      Select.finished = true;
    }
  }, 200);
};

//下拉显示值
const getLabel = (obj: any, fields: string) => {
  let matchs = fields.match(/\w+/g);
  if (matchs == null) {
    return "";
  }
  matchs.forEach((element) => {
    fields = fields.replace(element, obj[element]);
  });
  return fields;
};
//默认加载
loadMore(reSelect);
</script>

<template>
  <el-select
    v-model="modelCpd"
    v-loadMore:[reSelect]="loadMore"
    :popper-class="reSelect.name"
    :multiple="props.multiple"
    clearable
    collapse-tags
    collapse-tags-tooltip
    :placeholder="props.placeholder"
    filterable
    :disabled="props.disabled"
    @change="(value:any) => {
			if(props.change != null)
			{
				props.change(value)
			}
		}"
  >
    <el-option
      v-for="item in reSelect.optionList"
      :key="item[props.key]"
      :value="item[props.value]"
      :label="getLabel(item, props.label ? props.label : 'Name')"
    />
  </el-select>
</template>

页面调用

<template>
    <scrollSelect
              v-model="state.EquipmentList"
              :name="'Equipment'"
              :methods="接口方法"
              :label="'EquipmentName-EquipmentCode'"
              :multiple="true"
    />
</template>

<script setup lang="ts">
import scrollSelect from "/@/components/scrollSelect/Index.vue";
</script>

效果