PB 循环删除树的所有根节点

//循环删除树的所有根结点
  long ll_handle,ll_handleNext
  ll_handleNext=0
  ll_handle = tv_1.finditem(RootTreeItem! ,0)

  do while ll_handle >0
      ll_handleNext = tv_1.finditem(NextTreeItem! ,ll_handle) //同级的下一个节点
    tv_1.deleteitem( ll_handle)
    ll_handle=ll_handleNext
    loop