How to set value for table lines in web dynpro ?

Hi experts,

I'm new in webdynpro. My requirement is to set value to the second line when user press expand on first line.

In method ONACTIONLOAD_CHILDREN , I use  get_static_attributes_table to get the current table records and change return table value .

Then i user bind_table to pass table to the screen.

It works fine for first time i press expand and collaps, but when i expand it again it throw out a dump 'OBJECTS_OBJREF_NOT_ASSIGNED'.

Could any one please help to solve that?

Thanks