el-cascader使用问题

1.关闭el-cascader清空选择：清空v-model绑定值即可；

2. props lazyLoad调用methods中方法：

 1 export default {
 2   data() {
 3     let self = this
 4     return {
 5         props: {    
 6             lazy: true,
 7             checkStrictly: true,
 8             async lazyLoad (node, resolve) {
 9                 ...
10                 self.method() //methods中方法
11                 ...
12            }

3. 每次打开el-cascader都刷新里面的数据：

　　尝试过用this.$refs.cascader.panel.lazyLoad()方法，结果报

[Vue warn]: Error in v-on handler: "TypeError: Cannot read property 'panel' of undefined"
TypeError: Cannot read property 'panel' of undefined

　　最后通过改变key绑定值实现

<el-cascader 
    v-model="value" 
    :props="props" 
    :show-all-levels="false" 
    @change="handleChange"
    ref="cascader"
    :key="refresh"
/> 

 1 export default {
 2     data() {
 3         return {
 4             Refresh:0,
 5         },
 6     methods: {
 7         method(){
 8             ++this.refresh;
 9             ...
10         }