RADIO_BUTTON controls allow the user to select single mutually exclusive options on a form (e.g. sex: male / female). The user cicks on a RADIO_BUTTON to select it. If it is currently selected, clicking on it has no affect. If it is currently deselected, clicking on it selects it and deselects any other RADIO_BUTTON in the same group. Multiple RADIO_BUTTONs in the same group cannot normally be selected at the same time (although the programmer can override this).RADIO_BUTTONs must be bound to a form via a CHECK_FRAME. All RADIO_BUTTONs to be used as one group are bound by a single CHECK_FRAME. Multiple groups of RADIO_BUTTONs are allowed via seperate CHECK_FRAMEs. CHECKBOXs and RADIO_BUTTONs can be mixed in the same CHECK_FRAME.
When RADIO_BUTTONs and CHECKBOXs are mixed in the same CHECK_FRAME, the behaviour tends to be (can be overriden by the programmer, but by default is):
- clicking on a RADIO_BUTTON that is selected does NOT affect other RADIO_BUTTONs and CHECKBOXs
- clicking on a RADIO_BUTTON that is NOT selected DOES affect other RADIO_BUTTONs and CHECKBOXs (they are all normally deselected)
It is possible to explicitly set the truth value of a CHECKBOX or RADIO_BUTTON control. This truth value is used by the CHECK_FRAME control to determin the value used when invoking the CHECK_FRAME log function. It is possible to overlap truth values from multiple CHECKBOX and RADIO_BUTTON controls. Using carfully selected values (sets of bits) it is possible to use one RADIO_BUTTON or CHECKBOX control to activate several other RADIO_BUTTON or CHECKBOX controls simultaniously.