customized dropdownlist

Yii 1.1 General Discussion
1

i have 2 table like this

category table


cid 

  1  

  2  

  3  

  4

category_parent table


child_id parent_id

   2         1

   3         1

   4         2

i want to create this drop down list with activeDropDownList


-1

--2

---4

--3

at now i can create drop down like this


1

2

3

4