请提供一个PB程序，树型结构

建立一个tv_1控件
long rows,i,cur_len,p
string mycode,str,myname,mylabel
long handle_current,h1
treeviewitem item
treeviewitem newitem
h1=tv_1.finditem(currenttreeitem!,0)
handle_current=tv_1.finditem(childtreeitem!,h1)
if handle_current<0 then
tv_1.getitem(h1,item)
mylabel=item.label
p=pos(mylabel,"--")
mycode=mid(mylabel,1,p - 1)
cur_len=len(mycode)
str="id like'"+mycode+"%'"
dw_1.setfilter(str)
dw_1.filter()
rows=dw_1.rowcount()
for i=1 to rows
mycode=dw_1.getitemstring(i,"no")
myname=dw_1.getitemstring(i,"name")
if len(mycode)=cur_len+2 then
newitem.label=mycode+"--"+myname
newitem.pictureindex=(cur_len+2)/2+1
newitem.selectedpictureindex=(cur_len+2)/2+2
tv_1.insertitemlast(h1,newitem)
end if
next
end if
tv_1.expanditem(h1)
return 0