How to: Display a Non-Persistent Object's Detail View

• Jul 05, 2019
• 5 minutes to read

Show a Non-Persistent Object from the Navigation

1. Declare a non-persistent class, apply the DomainComponentAttribute to it, and add an object key property.

   C#

   using DevExpress.ExpressApp.DC;
   // ...
   [DomainComponent]
   public class NonPersistentObject {
       [Browsable(false)]
       [DevExpress.ExpressApp.Data.Key]
       public int Oid { get; set; }
       public string Name { get; set; }
   }
   

   VB.NET

   Imports DevExpress.ExpressApp.DC
   ' ...
   <DomainComponent> _
   Public Class NonPersistentObject
       <Browsable(False), DevExpress.ExpressApp.Data.Key> _
       Public Property Oid() As Integer
       Public Property Name() As String
   End Class
   

   Note

   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).

2. Rebuild the solution.

3. Run the Model Editor for a module project and add a new navigation item. Note that Mobile applications show only the Default navigation group content. Set the IModelNavigationItem.View property to the identifier of the Detail View to be displayed (e.g., NonPersistentObject_DetailView). Set the IModelNavigationItem.ObjectKey property to an arbitrary integer value. Note that this value should be unique if you want to display different non-persistent objects of this type.

   

4. Open the WinApplication.cs (WinApplication.vb), WebApplication.cs (WebApplication.vb), and/or MobileApplication.cs (MobileApplication.vb) file in a C#/VB Editor. Ensure that the NonPersistentObjectSpaceProvider is registered in the overridden CreateDefaultObjectSpaceProvider method (in addition to the existing XPObjectSpaceProvider or EFObjectSpaceProvider). The Solution Wizard adds this code automatically. Note that this code may be missing if you created your project in an older XAF version.

   C#

   protected override void CreateDefaultObjectSpaceProvider(CreateCustomObjectSpaceProviderEventArgs args) {
       // ...
       args.ObjectSpaceProviders.Add(new NonPersistentObjectSpaceProvider(TypesInfo, null));
   }
   

   VB.NET

   Protected Overrides Sub CreateDefaultObjectSpaceProvider(ByVal args As CreateCustomObjectSpaceProviderEventArgs)
       ' ...
       args.ObjectSpaceProviders.Add(New NonPersistentObjectSpaceProvider(TypesInfo, Nothing))
   End Sub
   

5. Create a WindowController descendant and handle the NonPersistentObjectSpace.ObjectByKeyGetting event. In the event handler, get an instance of the predefined non-persistent object with a key specified at the previous step.

   C#

   using DevExpress.ExpressApp;
   // ...
   public class NonPersistentObjectsController : WindowController {
       private void Application_ObjectSpaceCreated(object sender, ObjectSpaceCreatedEventArgs e) {
           NonPersistentObjectSpace nonPersistentObjectSpace = e.ObjectSpace as NonPersistentObjectSpace;
           if(nonPersistentObjectSpace != null) {
               nonPersistentObjectSpace.ObjectByKeyGetting += nonPersistentObjectSpace_ObjectByKeyGetting;
           }
       }
       private void nonPersistentObjectSpace_ObjectByKeyGetting(object sender, ObjectByKeyGettingEventArgs e) {
           if(e.ObjectType.IsAssignableFrom(typeof(NonPersistentObject))) {
               if(((int)e.Key) == 138) {
                   NonPersistentObject obj138 = new NonPersistentObject();
                   obj138.Key = 138;
                   obj138.Name = "Sample Object";
                   e.Object = obj138;
               }
           }
       }
       protected override void OnActivated() {
           base.OnActivated();
           Application.ObjectSpaceCreated += Application_ObjectSpaceCreated;
       }
       protected override void OnDeactivated() {
           base.OnDeactivated();
           Application.ObjectSpaceCreated -= Application_ObjectSpaceCreated;
       }
       public NonPersistentObjectsController() {
           TargetWindowType = WindowType.Main;
       }
   }
   

   VB.NET

   Imports Microsoft.VisualBasic
   Imports DevExpress.ExpressApp
   ' ...
   Public Class NonPersistentObjectsController
       Inherits WindowController
   
       Private Sub Application_ObjectSpaceCreated(ByVal sender As Object, ByVal e As ObjectSpaceCreatedEventArgs)
           Dim nonPersistentObjectSpace As NonPersistentObjectSpace = TryCast(e.ObjectSpace, NonPersistentObjectSpace)
           If nonPersistentObjectSpace IsNot Nothing Then
               AddHandler nonPersistentObjectSpace.ObjectByKeyGetting, AddressOf nonPersistentObjectSpace_ObjectByKeyGetting
           End If
       End Sub
       Private Sub nonPersistentObjectSpace_ObjectByKeyGetting(ByVal sender As Object, ByVal e As ObjectByKeyGettingEventArgs)
           If e.ObjectType.IsAssignableFrom(GetType(NonPersistentObject)) Then
               If (CInt(Fix(e.Key))) = 138 Then
                   Dim obj138 As New NonPersistentObject()
                   obj138.Key = 138
                   obj138.Name = "Sample Object"
                   e.Object = obj138
               End If
           End If
       End Sub
       Protected Overrides Sub OnActivated()
           MyBase.OnActivated()
           AddHandler Application.ObjectSpaceCreated, AddressOf Application_ObjectSpaceCreated
       End Sub
       Protected Overrides Sub OnDeactivated()
           MyBase.OnDeactivated()
           RemoveHandler Application.ObjectSpaceCreated, AddressOf Application_ObjectSpaceCreated
       End Sub
       Public Sub New()
           TargetWindowType = WindowType.Main
       End Sub
   End Class
   

   To create a new non-persistent object for each Detail View, leave the ObjectKey value empty at the previous step and create the following View Controller:

   C#

   using DevExpress.ExpressApp;
   // ...
   public class NonPersistentObjectActivatorController : ObjectViewController<DetailView, NonPersistentObject> {
       protected override void OnActivated() {
           base.OnActivated();
           if ((ObjectSpace is NonPersistentObjectSpace) && (View.CurrentObject == null)) {
               View.CurrentObject = View.ObjectTypeInfo.CreateInstance();
               View.ViewEditMode = DevExpress.ExpressApp.Editors.ViewEditMode.Edit;
           }
       }
   }
   

   VB.NET

   Imports DevExpress.ExpressApp
   ' ...
   Public Class NonPersistentObjectActivatorController
       Inherits ObjectViewController(Of DetailView, NonPersistentObject)
   
       Protected Overrides Sub OnActivated()
           MyBase.OnActivated()
           If (TypeOf ObjectSpace Is NonPersistentObjectSpace) AndAlso (View.CurrentObject Is Nothing) Then
               View.CurrentObject = View.ObjectTypeInfo.CreateInstance()
               View.ViewEditMode = DevExpress.ExpressApp.Editors.ViewEditMode.Edit
           End If
       End Sub
   End Class
   

   This Controller uses the default object’s constructor to create a new instance. You can also pass arguments to the CreateInstance(Object[]) method to use another constructor.

Show Non-Persistent Objects in a Dashboard View

To show non-persistent objects in a DashboardView, follow the steps from the previous section and create a dashboard item instead of the navigation item. Refer to the DashboardView class description for information on how a Detail View binds to a Dashboard View item.

Show a Non-Persistent Object in a Modal Dialog Window

1. Implement a PopupWindowShowAction Action.
2. Handle its PopupWindowShowAction.CustomizePopupWindowParams event.

3. In the event handler:

   • use the CreateObjectSpace(Type) method to create an Object Space for the non-persistent type;
   • use the XafApplication.CreateDetailView method to create a Detail View for the non-persistent type;
   • set the CustomizePopupWindowParamsEventArgs.View property to this Detail View.

Refer to the Ways to Show a View and Ways to Show a Confirmation Dialog topics for more information and examples.

Show a Non-Persistent Dialog from a Business Class

To execute simple business logic and prompt a user for parameters, use the ActionAttribute as shown in the How to: Create an Action Using the Action Attribute topic.