一：
写好结构

<el-form-item label="级别" prop="level"><el-select v-model="form.level" placeholder="请选择级别"><el-optionv-for="item in levelList":key="item.value":label="item.label":value="item.value"></el-option></el-select></el-form-item><el-form-item label="上级"><el-select v-model="form.parentId" clearable placeholder="上级"><el-optionv-for="item in parentList":key="item.id":label="item.name":value="item.id"/></el-select></el-form-item>

二：data(){}的数据

levelList:[{label: '一级',value: '1'},{label: '二级',value: '2'},{label: '三级',value: '3'}],form: {name: '',code: '',remark: '',level: '',parentId: ''}parentList: [],

三：监听特定的值

watch: {'form.level': {immediate: true,// handler:是一个回调函数，即监听到变化应该执行的函数handler(value) {if (value) {// 清空数据this.form.parentId = ''this.getDataTableList(value)}}}},

四：传被监听到的参数id ,调接口获取下拉框数据

getDataTableList(parentId) {getParentData(parentId - 1).then(response => {if (response.success) {console.log(response);this.parentList = response.data}})},