怎么判断delphi tlistview 某项为空

tlistview 如果输入不全需要给出提示

怎么判断呢？

---

if selected.caption='' then ...

for i:=0 to selected.subiteems.count-1 do
if selected.subitems[i]='' then ...

---

遍历所有listitem
for i:=0 to listview.items.count -1 do
begin
if listview.items[i].caption='' then
  begin
    showmessage('该项为空');
    break;
    end;
for j:=0 to listview.items[i].subitems.count-1 do
if listview.items[i].subitems[j]=''
  begin
    showmessage('该项为空'); 
    break;
  end;
end;