27 Understanding Radio Button Controls

This chapter contains the following topics:

27.1 Radio Button Controls

Use radio buttons to indicate choices. Selecting a radio button indicates which function in a set of functions is to be enabled. Radio button option sets should always be mutually exclusive. Enclose a set of radio button controls in a group box control to make them function as a single unit.

You can associate radio buttons with a user-defined code (UDC) field, where each button has a value from the UDC table. You must associate a radio button with a database or data dictionary (DD) item.

27.2 Radio Button Design-Time Considerations

A standard use case for a group of radio buttons is to provide users with a choice of operators to use in a query. If you want to use radio buttons for this purpose, use the Filter Criteria property options.

By default, the control returns a Boolean numeric value to indicate its state (0 for deselected and 1 for selected). However, you can change the return value for a radio button control with the Value property.

27.3 Radio Button Events

Only one event occurs on a radio button control: Selection Changed. Runtime fires the event when the user changes the status of a radio button. Consequently, Selection Changed should occur in pairs for radio buttons: Once for the selected control and once for the control that the system deselects.