how to make checkbox editable

Hi All

I am using class cl_salv_table to create the alv.

My need is to make check box.

i am using code

gr_column->set_cell_type( if_salv_c_cell_type=>checkbox ).

Checkbox is coming but it is in display mode.

can anyboy suggest how can i make it editable.

Thanks and Regards

Aditya