<com:TContent ID="Content"> <com:TRequiredFieldValidator ControlToValidate="rad_button_list" Text="You must click one" Display="Dynamic" ValidationGroup="Group" /> <br /> <com:TActiveRadioButtonList ID="rad_button_list" OnCallback="radChange"> <com:TListItem Value="yes" Text="Yes" /> <com:TListItem Value="no" Text="No" /> <com:TListItem Value="whynot" Text="Why not?" /> </com:TActiveRadioButtonList> <br /> <com:TActiveLabel ID="label" Text="Choice : " /> <br /><br /><br /> <com:TActiveButton ID="action_button" Text="action" OnCallback="action" ValidationGroup="Group" /> </com:TContent>