[Expand]General Information
[Expand]WinForms Controls
[Expand]ASP.NET Controls and MVC Extensions
[Expand]ASP.NET Bootstrap Controls
[Expand]ASP.NET Core Bootstrap Controls
[Expand]WPF Controls
[Expand]Xamarin Controls
[Expand]Windows 10 App Controls
[Expand]Office File API
[Expand]Report and Dashboard Server
[Collapse]eXpressApp Framework
 [Expand]Getting Started
 [Expand]Design-Time Features
 [Collapse]Task-Based Help
  [Collapse]Business Model Design
   [Expand]Common Tasks
   [Expand]Entity Framework (EF)
   [Expand]eXpress Persistent Objects (XPO)
   [Collapse]Non-Persistent Objects
     How to: Display a List of Non-Persistent Objects in a Popup Dialog
     How to: Display a Non-Persistent Object's Detail View from the Navigation
     How to: Display a Non-Persistent Object's List View from the Navigation
     How to: Display Non-Persistent Objects in a Report
     How to: Perform CRUD Operations with Non-Persistent Objects
     How to: Show Persistent Objects in a Non-Persistent Object's View
  [Expand]Application Model
  [Expand]List Editors
  [Expand]Property Editors
  [Expand]Scheduler and Notifications
  [Expand]Maps Module
  [Expand]Miscellaneous UI Customizations
  Frequently Asked Questions (FAQ)
 [Expand]API Reference
[Expand]eXpress Persistent Objects
[Expand]CodeRush Classic
[Expand]Cross-Platform Core Libraries
[Expand]Tools and Utilities
 End-User Documentation
View this topic on docs.devexpress.com (Learn more)

How to: Display a List of Non-Persistent Objects in a Popup Dialog

This example demonstrates how to populate and display a list of objects that are not bound to the database (Non-Persistent Objects). A sample application that stores a list of books will be created in this example. An Action that displays a list of duplicate books in a pop-up window will be added to this application.


Mobile applications do not show objects from collection properties in Detail Views. To implement this functionality in the Mobile UI, show a List View as described in the How to: Display a Non-Persistent Object's List View from the Navigation topic.


A complete sample project is available in the DevExpress Code Examples database at http://www.devexpress.com/example=E980.

  1. Define the Book persistent class.

    The Book class, as its name implies, is used to represent books. It inherits BaseObject, and thus it is persistent. It contains a single Title property, which stores a book's title.

  2. Define two non-persistent classes - Duplicate and DuplicatesList.


    The INotifyPropertyChanged, IXafEntityObject and IObjectSpaceLink interface implementations were omitted in this example. However, it is recommended to support these interfaces in real-world applications (see PropertyChanged Event in Business Classes and Non-Persistent Objects).

    These classes are not inherited from an XPO base persistent class, and are not added to the Entity Framework data model. As a result, they are not persistent. The DomainComponentAttribute applied to these classes indicates that these classes should be added to the Application Model and thus will participate in UI construction. The Duplicate non-persistent class has three public properties - Title, Count and Id. The Title property stores the title of a book. The Count property stores the total number of books with the title specified by the Title property. Id is a key property. It is required to add a key property to a non-persistent class and provide a unique key property value for each class instance in order for the ListView to operate correctly. To specify a key property, use the KeyAttribute. The DuplicatesList non-persistent class aggregates the duplicates via the Duplicates collection property of the BindingList<Duplicate> type.

  3. Create the following ShowDuplicateBooksController View Controller.

    This Controller inherits ObjectViewController<ListView, Book>, and thus, targets List Views that display Books. In the Controller's constructor, the ShowDuplicateBooks PopupWindowShowAction is created. In the Action's PopupWindowShowAction.CustomizePopupWindowParams event handler, the Books are iterated to find the duplicates. For each duplicate book found, the Duplicate object is instantiated and added to the DuplicatesList.Duplicates collection. Note that a unique key value (Id) is assigned for each Duplicate. Finally, a DuplicatesList Detail View is created and passed to the handler's CustomizePopupWindowParamsEventArgs.View parameter. As a result, a DuplicatesList object is displayed in a pop-up window when a user clicks ShowDuplicateBooks.

The following images illustrate the implemented Action and its pop-up window.

Windows Forms:


Expanded See Also

Is this topic helpful?​​​​​​​