Occurs when a group row is about to be collapsed, allowing cancellation of the action.
public event RowAllowEventHandler GroupRowCollapsing
Public Event GroupRowCollapsing As RowAllowEventHandler
The GroupRowCollapsing event handler receives an argument of the DevExpress.UI.Xaml.Grid.RowAllowEventArgs type.
The GroupRowCollapsing event is raised before a group row is collapsed by an end-user or in code, allowing you to cancel this action. The group row is identified by its handle via the RowHandle property. To prevent the group row from being collapsed, set the event parameter's Allow parameter to false.
The GridControl.CollapseAllGroups method allows you to collapse all group rows. In this instance, the GroupRowCollapsing event is raised only once. The event parameter's RowHandle property returns an invalid row handle (DataControlBase.InvalidRowHandle).
After the group row has been collapsed, the GridControl.GroupRowCollapsed event is raised.