Asynchronously retrieves an object from another Object Space to the current Object Space or gets a wrapped object (i.e., wrapped in XafDataViewRecord or XafInstantFeedbackRecord).
Namespace: DevExpress.ExpressApp.Xpo
Assembly: DevExpress.ExpressApp.Xpo.v19.2.dll
| Name | Type | Description |
|---|---|---|
| obj | Object | An object that represents a template object from another Object Space. |
| cancellationToken | CancellationToken | A CancellationToken object that delivers a cancellation notice to the running operation. |
| Name | Type | Description |
|---|---|---|
| obj | Object | An object that represents a template object from another Object Space. |
| cancellationToken | CancellationToken | A CancellationToken object that delivers a cancellation notice to the running operation. |
| Name | Type | Description |
|---|---|---|
| obj | Object | An object that represents a template object from another Object Space. |
| cancellationToken | CancellationToken | A CancellationToken object that delivers a cancellation notice to the running operation. |
| Type | Description |
|---|---|
| Task<Object> | A Task that returns an object. This object represents the evaluated value. |
| Type | Description |
|---|---|
| Task<Object> | A Task that returns an object. This object represents the evaluated value. |
| Type | Description |
|---|---|
| Task<Object> | A Task that returns an object. This object represents the evaluated value. |
This method retrieves the object specified as the obj parameter from the database via the current Object Space's XPObjectSpace.Session. If the passed object is not persistent, it's returned as is.
The following code demonstrates how you can use this method in a View Controller to find and show a Contact the selected DemoTask is assigned to. If this DemoTask is not assigned to any Contact, a Detail View for a new Contact object is shown.
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.Xpo;
using System;
using System.Threading;
// ...
public class AsyncAssignedToInfoController : ObjectViewController<ListView, DemoTask> {
View contactView = null;
public AsyncAssignedToInfoController() : base() {
SimpleAction showAssignedToInfoAction = new SimpleAction(this, "Assigned contact's info", "Edit");
showAssignedToInfoAction.SelectionDependencyType = SelectionDependencyType.RequireSingleObject;
showAssignedToInfoAction.Execute += showAssignedToInfoAction_Execute;
}
async private void showAssignedToInfoAction_Execute(object sender, SimpleActionExecuteEventArgs e) {
CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
XPObjectSpace contactObjectSpace = (XPObjectSpace)Application.CreateObjectSpace(typeof(Contact));
contactView = Application.CreateDetailView(contactObjectSpace, "Contact_DetailView", true);
e.ShowViewParameters.CreatedView = contactView;
Contact assignedTo = (Contact)ViewCurrentObject.AssignedTo;
if (assignedTo != null) {
object obj = await contactObjectSpace.GetObjectAsync(assignedTo, cancellationTokenSource.Token);
contactView.CurrentObject = obj ?? contactObjectSpace.CreateObject(typeof(Contact));
}
else {
contactView.CurrentObject = contactObjectSpace.CreateObject(typeof(Contact));
}
if (contactObjectSpace.IsNewObject(contactView.CurrentObject)) {
contactObjectSpace.Committed += contactObjectSpace_Committed;
}
}
private void contactObjectSpace_Committed(object sender, EventArgs e) {
ViewCurrentObject.AssignedTo = ObjectSpace.GetObject(contactView.CurrentObject) as Contact;
}
}
Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.ExpressApp.Xpo
Imports System
Imports System.Threading
' ...
Public Class AsyncAssignedToInfoController
Inherits ObjectViewController(Of ListView, DemoTask)
Private contactView As View = Nothing
Public Sub New()
MyBase.New()
Dim showAssignedToInfoAction As New SimpleAction(Me, "Assigned contact's info", "Edit")
showAssignedToInfoAction.SelectionDependencyType = SelectionDependencyType.RequireSingleObject
AddHandler showAssignedToInfoAction.Execute, AddressOf showAssignedToInfoAction_Execute
End Sub
Private Async Sub showAssignedToInfoAction_Execute(ByVal sender As Object, ByVal e As SimpleActionExecuteEventArgs)
Dim cancellationTokenSource As New CancellationTokenSource()
Dim contactObjectSpace As XPObjectSpace = CType(Application.CreateObjectSpace(GetType(Contact)), XPObjectSpace)
contactView = Application.CreateDetailView(contactObjectSpace, "Contact_DetailView", True)
e.ShowViewParameters.CreatedView = contactView
Dim assignedTo As Contact = CType(ViewCurrentObject.AssignedTo, Contact)
If assignedTo IsNot Nothing Then
Dim obj As Object = Await contactObjectSpace.GetObjectAsync(assignedTo, cancellationTokenSource.Token)
contactView.CurrentObject = If(obj, contactObjectSpace.CreateObject(GetType(Contact)))
Else
contactView.CurrentObject = contactObjectSpace.CreateObject(GetType(Contact))
End If
If contactObjectSpace.IsNewObject(contactView.CurrentObject) Then
AddHandler contactObjectSpace.Committed, AddressOf contactObjectSpace_Committed
End If
End Sub
Private Sub contactObjectSpace_Committed(ByVal sender As Object, ByVal e As EventArgs)
ViewCurrentObject.AssignedTo = TryCast(ObjectSpace.GetObject(contactView.CurrentObject), Contact)
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.