TDBLookupListBox.KeyDown procedure

Declaration

procedure KeyDown(var Key: Word; Shift: TShiftState); override

Arguments

Description

KeyDown is an overridden procedure used to apply the specified virtual key code and modifier to the control.

Key is the virtual key code examined in the method. Shift is the modifier for the virtual key code.

KeyDown ensures that the NullValueKey shortcut defined for the control is applied to the control and its lookup dataset in the internal TDBLookup instance. This causes the value in ItemIndex to be set to -1 to clear the selection in the listbox.

KeyDown calls the inherited method prior to exit.

See also

• NullValueKey
• TDataLink.Active
• TCustomListBox.ItemIndex