As introduced above, each control belongs to a particular type. The compiler knows the following type names:
ACTIVE-X
BAR
BITMAP
CHECK-BOX
COMBO-BOX
ENTRY-FIELD
FRAME
GRID
LABEL
LIST-BOX
PUSH-BUTTON
RADIO-BUTTON
SCROLL-BAR
STATUS-BAR
TAB
TREE-VIEW
WEB-BROWSER
Control type names are reserved by the compiler.
When you create a control, a handle to the control is also created. This handle is a COBOL data item that uniquely identifies the control to the system. The handle values are generated dynamically by the system at runtime and cannot be controlled by the programmer.
In order to provide a constant name for the control that is the same between runs, you can optionally assign an ID to the control. The ID is a programmer assigned number. Anytime the runtime returns information about a control, it includes both its handle and its ID. Since the handle can change from run to run, examining the ID can be more convenient. A control's ID is the only effective way to distinguish controls in a Screen Section because those controls' handlesare hidden from the programmer.