IObjectSpaceAsync.ReloadObjectAsync(Object, CancellationToken) Method

Asynchronously reloads the state of the specified persistent object and its aggregated objects from the data store.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

Task<object> ReloadObjectAsync(
    object obj,
    CancellationToken cancellationToken = default(CancellationToken)
)

VB.NET

Function ReloadObjectAsync(
    obj As Object,
    cancellationToken As CancellationToken = Nothing
) As Task(Of Object)

Parameters

Name	Type	Description
obj	Object	An object that represents the persistent object whose state needs to be reloaded.

Optional Parameters

Name	Type	Default	Description
cancellationToken	CancellationToken	null	A CancellationToken object that delivers a cancellation notice to the running operation.

Returns

Type	Description
Task<Object>	A Task that returns an object. This object is the object specified by the obj parameter after it has been reloaded.

Remarks

If the specified persistent object is a new object, the ReloadObjectAsync method does nothing. To ensure that the persistent object is not a new object, use the XPObjectSpace.IsNewObject method.

The specified object can belong to another Object Space. In this case, the current Object Space retrieves the object and then reloads its state.

A CannotReloadPurgedObjectException occurs if the specified persistent object is permanently deleted from the data store.

The following code demonstrates how you can use this method in a View Controller to refresh a List View after a user changes an object on a Detail View and commits these changes. In this scenario, the List View should be read-only.

C#

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.Win.Editors;
using DevExpress.ExpressApp.Xpo;
using System.Threading;
// ...
public class AsyncUpdateListViewController : ObjectViewController<ListView, DemoTask> {
    public AsyncUpdateListViewController() : base() {
        SimpleAction updateListViewAction = new SimpleAction(this, "Open assigned contact", "Edit");
        updateListViewAction.SelectionDependencyType = SelectionDependencyType.RequireSingleObject;
        updateListViewAction.Execute += updateListViewAction_Execute;
    }
    private void updateListViewAction_Execute(object sender, SimpleActionExecuteEventArgs e) {
        object assignedContact = ViewCurrentObject.AssignedTo;
        IObjectSpace contactObjectSpace = Application.CreateObjectSpace(assignedContact.GetType());
        View contactView = Application.CreateDetailView(contactObjectSpace, contactObjectSpace.GetObject(assignedContact), true);
        e.ShowViewParameters.CreatedView = contactView;
        contactObjectSpace.Committed += async (s, args) => {
            CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
            await ((XPObjectSpace)ObjectSpace).ReloadObjectAsync(assignedContact, cancellationTokenSource.Token);
            if (View.Editor is GridListEditor) {
                GridListEditor gridListEditor = (GridListEditor)View.Editor;
                gridListEditor.GridView.LayoutChanged();
            }
        };
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.ExpressApp.Win.Editors
Imports DevExpress.ExpressApp.Xpo
Imports System.Threading
' ...
Public Class AsyncUpdateListViewController
    Inherits ObjectViewController(Of ListView, DemoTask)
    Public Sub New()
        MyBase.New()
        Dim updateListViewAction As New SimpleAction(Me, "Open assigned contact", "Edit")
        updateListViewAction.SelectionDependencyType = SelectionDependencyType.RequireSingleObject
        AddHandler updateListViewAction.Execute, AddressOf updateListViewAction_Execute
    End Sub
    Private Sub updateListViewAction_Execute(ByVal sender As Object, ByVal e As SimpleActionExecuteEventArgs)
        Dim assignedContact As Object = ViewCurrentObject.AssignedTo
        Dim contactObjectSpace As IObjectSpace = Application.CreateObjectSpace(assignedContact.GetType())
        Dim contactView As View = Application.CreateDetailView(contactObjectSpace, contactObjectSpace.GetObject(assignedContact), True)
        e.ShowViewParameters.CreatedView = contactView
        AddHandler contactObjectSpace.Committed, Async Sub(s, args)
            Dim cancellationTokenSource As New CancellationTokenSource()
            Await (CType(ObjectSpace, XPObjectSpace)).ReloadObjectAsync(assignedContact, cancellationTokenSource.Token)
            If TypeOf View.Editor Is GridListEditor Then
                Dim gridListEditor As GridListEditor = CType(View.Editor, GridListEditor)
                gridListEditor.GridView.LayoutChanged()
            End If
        End Sub
    End Sub
End Class

In the current example, the cancellationToken parameter is used for demonstration purposes. You can skip it or use to cancel an asynchronous operation as shown in the CancellationToken topic.