ViewItem Class

Represents a base class for View Items.

Namespace : DevExpress.ExpressApp.Editors

Assembly : DevExpress.ExpressApp.v25.2.dll

NuGet Package : DevExpress.ExpressApp

Declaration

C#
VB.NET

csharp

public abstract class ViewItem :
    IDisposable

Public MustInherit Class ViewItem
    Implements IDisposable

The following members return ViewItem objects:

Remarks

The ViewItem class implements basic functionality for items that can be contained in a Detail View. This functionality includes:

The capability to display View Items via a specified control in a UI. Basically, a Detail View’s representation in a UI is a set of controls that display View Items.
A View Item can be related to the object that the parent Detail View presents. For instance, the PropertyEditor, being the ViewItem class’ descendant, represents the properties of the object presented by the Detail View.
A View Item can be refreshed when the parent Detail View is refreshed. Refreshing is assumed to be data related.
The capability to save the current settings of the control to the Application Model, so that the next time the control is created the same settings are used.

To access the Detail View in which a View Item is contained, use the ViewItem.View property.

XAF ships with the following descendants of the ViewItem class:

To implement a custom View Item, inherit from the ViewItem class. The following protected members that are not described in the documentation can be overridden:

Member	Description
`CreateControlCore`	Called by the ViewItem.CreateControl method. You should return the control that will represent your View Item in a UI.
`SaveModelCore`	Called by the ViewItem.SaveModel method. You can override it to save the settings of a View Item and its control to the Application Model. This allows display of the View Item in the same manner as it was before it was recreated.
`Dispose`	Called by the ViewItem.Dispose method. Override it if you need to dispose custom allocated resources.
`OnCurrentObjectChanging` and `OnCurrentObjectChanged`	Called when the ViewItem.CurrentObject property is changed.
`OnControlCreating` and `OnControlCreated`	Called when a control (see ViewItem.Control) is created. Raise the ViewItem.ControlCreating and ViewItem.ControlCreated events.

Note

A custom View Item should be implemented in a platform-specific application project and decorated with the ViewItemAttribute. This View Item will be loaded to the Application Model, which means that you will be able to use it in a UI.

For details on View Items and basics on how to implement custom ones, refer to the View Items and How to: Implement a View Item topics.

To access a View Item of the View for which a Controller is activated, handle the Controller.Activated and ViewItem.ControlCreated events, as it is demonstrated in the following article: Access the Settings of a Property Editor in a Detail View.