MDI Child

Gimana sih cara nyimpen pesan ke semua MDI child dari MDI induk?

Coba ini:

var
ChildIndex : Integer;
Form : TfrmChild;
begin

for ChildIndex := 0 to MDIChildCount - 1 do begin
Form := TfrmChild(MDIChildren[ChildIndex]);
if Form <> nil then
PostMessage(Form.Handle, WM_XXXX, 0, 0);
end;

end;