TreeList.BeforeLoadLayout Event
Occurs before a layout is restored from storage (a stream, xml file or the system registry).
Namespace: DevExpress.XtraTreeList
Assembly: DevExpress.XtraTreeList.v22.1.dll
NuGet Package: DevExpress.Win.TreeList
Declaration
Event Data
The BeforeLoadLayout event's data class is LayoutAllowEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| Allow | Gets or sets whether to allow upgrading the control layout. |
| NewHiddenItems | Returns an array of items that exist in the current control but do not exist in the layout being loaded. These items are hidden. This property is in effect for the LayoutControl. Inherited from LayoutUpgradeEventArgs. |
| PreviousVersion | Returns the textual representation of the previous layout version. Inherited from LayoutUpgradeEventArgs. |
Remarks
The BeforeLoadLayout event allows you to prevent the layout from being restored from storage and thus being applied to the control.
This event is fired when an attempt is made to restore a layout from storage using one of the following methods: TreeList.RestoreLayoutFromRegistry, TreeList.RestoreLayoutFromStream and TreeList.RestoreLayoutFromXml. To stop the layout from being restored from the storage set the event’s Allow parameter to false.
The event’s PreviousVersion parameter defines the version of the layout being restored. This can be compared with the version of the current layout specified by the OptionsLayoutBase.LayoutVersion (TreeList.OptionsLayout.LayoutVersion) property. The restoring of the layout can be cancelled, for instance if the versions do not match.