FilterController Class

Represents a ViewController descendant that contains the FullTextSearch and SetFilter Actions.

Namespace: DevExpress.ExpressApp.SystemModule

Assembly: DevExpress.ExpressApp.v25.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#
VB.NET

public class FilterController :
    ViewController,
    IModelExtender,
    IFilterActionProvider

Public Class FilterController
    Inherits ViewController
    Implements IModelExtender,
               IFilterActionProvider

Remarks

The FilterController displays the FullTextSearch and SetFilter Actions.

ASP.NET Core Blazor

Filter Controller SetFilter Action in ASP.NET Core Blazor, DevExpress

Filter Controller FullTextSearch Action in ASP.NET Core Blazor, DevExpress

Windows Forms

Filter Controller SetFilter Action in Windows Forms, DevExpress

Filter Controller FullTextSearch Action in Windows Forms, DevExpress

For details on the FullTextSearch and SetFilter Actions, refer to the description of the FilterController.FullTextFilterAction and FilterController.SetFilterAction properties, that provide access to these Actions.

To customize the default behavior of the FullTextSearch and SetFilter Actions, you can inherit from this Controller, or subscribe to its events. In addition, you can access the Actions to modify their behavior.

This Controller does not have platform-specific descendants, and you can create your own descendants to change its behavior. When deriving from the FilterController, the following protected virtual methods are available, and can be overridden:

Method	When is it called?	Description
`SetupFilters`	Invoked when the `FilterController` is activated.	Applies the criteria that is set for the current List View’s IModelListView.Criteria property in the Application Model. In addition, creates items for the SetFilter Action using the ListView \| Filters node from the Application Model. Executes the SetFilter Action, setting the filter specified by the Filters node’s `CurrentFilterID` property.
`ApplyFilter`	First, it is invoked when the `FilterController` is activated to apply an initial filter. Second, it is invoked when the SetFilter Action is executed, to apply the selected filter.	Generates a CriteriaOperator from the passed criterion, and adds it to the `Criteria` collection of the current List View’ CollectionSource.
`GetToolTip`	Invoked to generate a tooltip for the SetFilter Action. The tooltip is formed from the criteria applied to the current View’s collection source.	If the Views \| View node defining the current List View has the `Criteria` property set, this method applies the specified criterion via the `ApplyCriteria` method. If the Views \| View \| Filters node exists for the current List View, its child nodes are used to populate the SetFilter Action’s Items collection. The item that is specified by the Filters node’s `CurrentFilterID` property is set as a selected item (see SingleChoiceAction.SelectedItem), and its criterion is applied to the List View via the `SetFilter` method.
`SetFilter`	Invoked as a result of executing the SetFilter Action.	The SetFilter Action’s SingleChoiceAction.Execute event handler. Applies the selected filter passed as the `Execute` event handler’s parameter, to the current List View, via the `ApplyFilter` method. In addition, it sets the selected filter for the `CurrentFilterID` property of the current View’s Views \| View node.
`FullTextSearch`	Invoked as a result of executing the FullTextSearch Action.	The FullTextSearch Action’s ParametrizedAction.Execute event handler. Using the `Execute` event arguments, it generates a `CriteriaOperator`, and adds it to the `Criteria` collection of the current List View’s CollectionSource. To generate the `CriteriaOperator`, the static `DevExpress.ExpressApp.Filtering.FullTextSearchCriteriaBuilder` class is used.
`OnCustomBuildCriteria`	Invoked by the `FullTextSearch` method.	Raises the FilterController.CustomBuildCriteria event. To implement a custom algorithm for building criteria in the `FilterController` class descendant, override this method. Set the `CustomBuildCriteriaEventArgs.Handled` parameter to `true`, to prohibit executing a default algorithm. Assign the generated criteria to the `CustomBuildCriteriaEventArgs.Criteria` parameter.
`CreateSearchCriteriaBuilder`	Invoked by the `FullTextSearch` method.	Creates a `SearchCriteriaBuilder` object to be used for building criteria. Override this method, to return an object of the custom class that implements the `ISearchCriteriaBuilder` interface. Note that in this instance, this object’s `BuildCriteria` method will be called to generate the criterion for the current List View.
`OnCustomGetFullTextSearchProperties`	Invoked by the `FullTextSearch` method.	Raises the FilterController.CustomGetFullTextSearchProperties event. To collect properties for a search in a custom way in the `FilterController` class descendant, override this method. Set the `CustomGetFullTextSearchPropertiesEventArgs.Handled` parameter to `true` to prohibit collecting the properties in the default manner. Assign the set of the collected properties to the `CustomGetFullTextSearchPropertiesEventArgs.Properties` parameter.
`RemoveFilter`	Invoked when the current List View’s ListView.Model property is changed (see View.ModelChanged), to remove the filter specified by the `Criteria` property of the List View’s Views \| View node.	Removes the passed criterion from the `Criteria` collection of the current List View’ CollectionSource.
`UpdateActionState`	Invoked as a result of changing the environment.	Checks whether the active or enabled state of the SetFilter and FullTextSearch Actions should be changed after the environment has been changed.

Public members are described individually in the documentation.

This Controller is activated for List Views only. To ascertain whether the Controller is active, use the Controller.Active property. If you need to know the reason for its deactivation or activation at runtime, use the DiagnosticInfo Action.

Information about the FilterController and its SetFilter and FullTextSearch Actions is available in the Application Model‘s ActionDesign node. To access it, use the Model Editor.