TCustomRadioGroup = class(TCustomGroupBox)
class PASCALIMPLEMENTATION TCustomRadioGroup : public Vcl::Stdctrls::TCustomGroupBox
TCustomRadioGroup is the base class for radio-group components.
Radio groups are collections of radio buttons in a single group box. TCustomRadioGroup is the class from which radio-group components—including TRadioGroup and TDBRadioGroup—descend.
Radio buttons that are contained directly in the same control component are said to be "grouped." When the user checks a radio button, all other radio buttons in its group become unchecked. Hence, two radio buttons on a form can be checked at the same time only if they are placed in separate containers, such as group boxes.