ASPxTreeList.BeforeHeaderFilterFillItems Event

Enables you to provide custom filter items instead of default ones displayed within a Header Filter.

Namespace: DevExpress.Web.ASPxTreeList

Assembly: DevExpress.Web.ASPxTreeList.v19.2.dll


public event ASPxTreeListBeforeHeaderFilterFillItemsEventHandler BeforeHeaderFilterFillItems
Public Event BeforeHeaderFilterFillItems As ASPxTreeListBeforeHeaderFilterFillItemsEventHandler

Event Data

The BeforeHeaderFilterFillItems event handler receives an argument of the ASPxTreeListBeforeHeaderFilterFillItemsEventArgs type. The following properties provide information specific to this event.

Property Description
Column Gets the data column currently being filtered.
Handled Specifies whether the BeforeHeaderFilterFillItems event is handled.
Values Gets a collection that contains the header filer values.


End-users can filter column values using the Header Filter. To invoke the header filter, an end-user should click on the filter button. The BeforeHeaderFilterFillItems event is raised before the header filter is shown and default filter items are created. The event enables you to provide custom filter items.

The data column whose filter button has been clicked is returned by the ASPxTreeListBeforeHeaderFilterFillItemsEventArgs.Column property. To add a new filter value, use the ASPxGridBeforeHeaderFilterFillItemsEventArgs.AddValue method.

Set the ASPxGridBeforeHeaderFilterFillItemsEventArgs.Handled property to true to prevent the ASPxTreeList.HeaderFilterFillItems event from being raised. Otherwise, the event clears the item collection before filling it with default items.

If you would like to add custom items to the default items, use the ASPxTreeList.HeaderFilterFillItems event.

The ASPxTreeList header filter allows the use of HTML tags in an item text. To learn more, see Header Filter .


Online Demos Refer to the Tree List - Header Filter (Web Forms) online demo to review how to filter Tree List data nodes using the Header Filter.

See Also