怠惰ロードツリー、親ノードがチェックされ、子ノードが怠惰ロードされた後もチェックされます.

<template>
<div class="deptTree">
  <el-button
    @click="test"
  > 
  </el-button>
  <!-- \ \ -->
  <el-tree
    ref="tree"
    show-checkbox
    accordion
    :load="handleLoad"
    lazy
    node-key="id"
    :default-expanded-keys="[rootNode.id]"
    :default-checked-keys="[]"
    :props="defaultProps"
    :expand-on-click-node="true"
    :highlight-current="true"
    :default-expand-all="false">
  </el-tree>
</div>
</template>

<script>
  export default {
    name: "deptTree",
    data(){
      return {
        defaultProps: {
          children: 'children',
          label: 'label'
        },
        content:'',
        treeData:[],
        rootKey:'00000002',
        rootNode : {
          id : "00000002",
          label : " "
        },
        checkedKeys : []
      }
    },
    methods: {
      /**
       *  
       */
      handleLoad(node, resolve) {
        //  key,  
        if(this.$refs.tree!=undefined) this.checkedKeys = this.$refs.tree.getCheckedKeys();
        if (node.level == 0) {
          return resolve([this.rootNode]);
        } else {
          var children = [
            {
              id : "00000003",
              label : " 1"
            },
            {
              id : "00000004",
              label : " 2"
            },
            {
              id : "00000005",
              label : " 3"
            }
          ];
          resolve(children);
        }
        if(this.$refs.tree!=undefined) this.$refs.tree.setCheckedKeys(this.checkedKeys);
      },
      test() {
        var checkedKeys = this.$refs.tree.getCheckedKeys();
        console.log(checkedKeys);
      }
    },
  }
</script>

<style scoped lang="scss">
</style>
<style lang="scss">
</style>