Dialog to Dialog communication

hi,

i have sub classed 2 dialogs,
In my 1st dialog class one button and one list box is there,whenever i click the button in the Dialog1 it should open dialog2,in that dialog2 some pushbuttons are there.whenever i clicked push buttons in the dialog2 some information should be added to the list box in the dialog1.

how to achieve this, give me the idea

thank you.

add a signal in the second dialog which will send needed information, then connect this signal with a needed slot in the first dialog.
what is the problem?