TTabControl.OnChanging property
Event handler signalled prior to changing the active tab/page on the tabbed control.
Declaration
property OnChanging:;Description
OnChanging is a
TTabChangingEvent property with the
event handler signalled prior to changing the active page/tab on the tabbed
control. OnChanging is signalled from the CanChange method, and occurs
immediately before the new value is applied to the PageIndex property.
An application can implement and assign a handler routine to the property to determine whether the PageIndex and the active tab/page can be changed.
The Sender argument is the TCustomTabControl for the event.
AllowChange is a variable argument which indicates whether
PageIndex can be changed. When set to
True (the default), the value in
PageIndex can be updated. Otherwise, the value in PageIndex is not updated.
This description is the one of ComCtrls.TCustomTabControl.OnChanging.
See also
An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.