Refresh Objects and Rollback Changes

• Sep 14, 2022
• 4 minutes to read

Useful API

Members	Description
Methods:
IObjectSpace.Refresh	Updates the persistent objects belonging to the current Object Space.
IObjectSpace.ReloadObject	Updates the specified object with data from the data source.
IObjectSpace.Rollback	Cancels the changes made to the persistent objects belonging to the current Object Space.
Events:
IObjectSpace.Refreshing	Occurs before refreshing the current Object Space’s persistent objects.
IObjectSpace.Reloaded	Occurs after the current Object Space reconnects to the database.
IObjectSpace.ObjectReloaded	Occurs after an object is reloaded from the database.
IObjectSpace.CustomRefresh	Replace the default processes of refreshing persistent objects with a custom one.
IObjectSpace.RollingBack	Occurs before rolling back the changes made to the current Object Space’s persistent objects.
IObjectSpace.CustomRollBack	Replaces the default process of persistent objects rollback with a custom one.

In your code, you can modify business objects to create new ones, delete objects or edit objects’ properties. If you perform this in an ObjectSpace different from the current View’s ObjectSpace, refresh the current View’s ObjectSpace to show changes in the View. Call the IObjectSpace.Refresh method to show new data in the View.

The example below adds a new Contact object to a List View and refreshes the Object Space to show the new object.

C#

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.Persistent.Base;
using MainDemo.Module.BusinessObjects;
// ...
public class AddContactController : ObjectViewController<ListView, Contact> {
    public AddContactController() {
        ParametrizedAction addContactAction = new ParametrizedAction(
            this, "AddContact", PredefinedCategory.Edit, typeof(string));
        addContactAction.Execute += AddContactAction_Execute;
    }
    private void AddContactAction_Execute(object sender, ParametrizedActionExecuteEventArgs e) {
        using(IObjectSpace objectSpace = Application.CreateObjectSpace(typeof(Contact))) {
            Contact contact = objectSpace.CreateObject<Contact>();
            contact.FirstName = e.ParameterCurrentValue as string;
            objectSpace.CommitChanges();
        }
        View.ObjectSpace.Refresh();
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.Persistent.Base
Imports MainDemo.Module.BusinessObjects

Public Class AddContactController
    Inherits ObjectViewController(Of ListView, Contact)
    Public Sub New()
        Dim addContactAction As New ParametrizedAction(Me, "AddContact", PredefinedCategory.Edit, GetType(String))
        AddHandler addContactAction.Execute, AddressOf AddContactAction_Execute
    End Sub
    Private Sub AddContactAction_Execute(ByVal sender As Object, ByVal e As ParametrizedActionExecuteEventArgs)
        Using objectSpace As IObjectSpace = Application.CreateObjectSpace(GetType(Contact))
            Dim contact As Contact = objectSpace.CreateObject(Of Contact)()
            contact.FirstName = TryCast(e.ParameterCurrentValue, String)
            objectSpace.CommitChanges()
        End Using
        View.ObjectSpace.Refresh()
    End Sub
End Class

The following code reloads the parent Detail View when one of the child objects is reloaded.

C#

using DevExpress.ExpressApp;
using YourSolutionName.Module.BusinessObjects;

namespace YourSolutionName.Module.Controllers {
    public class MyViewController : ObjectViewController<DetailView, Parent> {
        protected override void OnActivated() {
            base.OnActivated();
            ObjectSpace.ObjectReloaded += ObjectSpace_ObjectReloaded;
        }
        private void ObjectSpace_ObjectReloaded(object sender, ObjectManipulatingEventArgs e) {
            Child child = e.Object as Child;
            if (child != null && ReferenceEquals(child.Parent, View.CurrentObject)) {
                View.Refresh();
            }
        }
        protected override void OnDeactivated() {
            ObjectSpace.ObjectReloaded -= ObjectSpace_ObjectReloaded;
            base.OnDeactivated();
        }
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports YourSolutionName.Module.BusinessObjects

Namespace YourSolutionName.Module.Controllers
    Public Class MyViewController
        Inherits ObjectViewController(Of DetailView, Parent)

        Protected Overrides Sub OnActivated()
            MyBase.OnActivated()
            AddHandler ObjectSpace.ObjectReloaded, AddressOf ObjectSpace_ObjectReloaded
        End Sub

        Private Sub ObjectSpace_ObjectReloaded(ByVal sender As Object, ByVal e As ObjectManipulatingEventArgs)
            Dim child As Child = TryCast(e.Object, Child)

            If child IsNot Nothing AndAlso ReferenceEquals(child.Parent, View.CurrentObject) Then
                View.Refresh()
            End If
        End Sub

        Protected Overrides Sub OnDeactivated()
            RemoveHandler ObjectSpace.ObjectReloaded, AddressOf ObjectSpace_ObjectReloaded
            MyBase.OnDeactivated()
        End Sub
    End Class
End Namespace

To reload an object changed in another Object Space in the current Object Space, use the IObjectSpace.ReloadObject method. The following controller demonstrates how to open a Popup Window to edit an Task object and then, reload this object in the Task List View.

C#

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.Editors;

public class EditTaskController : ObjectViewController<ListView, Task> {
    public EditTaskController() {
        PopupWindowShowAction action = new PopupWindowShowAction(this, "EditTask", DevExpress.Persistent.Base.PredefinedCategory.Edit);
        action.SelectionDependencyType = SelectionDependencyType.RequireSingleObject;
        action.CustomizePopupWindowParams += Action_CustomizePopupWindowParams;
        action.Execute += Action_Execute;
    }
    private void Action_Execute(object sender, PopupWindowShowActionExecuteEventArgs e) {
        e.PopupWindowView.ObjectSpace.CommitChanges();
        ObjectSpace.ReloadObject(e.PopupWindowViewCurrentObject);
    }

    private void Action_CustomizePopupWindowParams(object sender, CustomizePopupWindowParamsEventArgs e) {
        IObjectSpace objectSpace = Application.CreateObjectSpace(typeof(Task));
        Task task = (Task)objectSpace.GetObject(View.CurrentObject);
        DetailView detailView = Application.CreateDetailView(objectSpace, task);
        detailView.ViewEditMode = ViewEditMode.Edit;
        e.View = detailView;
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.ExpressApp.Editors

Public Class EditTaskController
    Inherits ObjectViewController(Of ListView, Task)

    Public Sub New()
        Dim action As PopupWindowShowAction = New PopupWindowShowAction(Me, "EditTask", DevExpress.Persistent.Base.PredefinedCategory.Edit)
        action.SelectionDependencyType = SelectionDependencyType.RequireSingleObject
        AddHandler action.CustomizePopupWindowParams, AddressOf Action_CustomizePopupWindowParams
        AddHandler action.Execute, AddressOf Action_Execute
    End Sub

    Private Sub Action_Execute(ByVal sender As Object, ByVal e As PopupWindowShowActionExecuteEventArgs)
        e.PopupWindowView.ObjectSpace.CommitChanges()
        ObjectSpace.ReloadObject(e.PopupWindowViewCurrentObject)
    End Sub

    Private Sub Action_CustomizePopupWindowParams(ByVal sender As Object, ByVal e As CustomizePopupWindowParamsEventArgs)
        Dim objectSpace As IObjectSpace = Application.CreateObjectSpace(GetType(Task))
        Dim task As Task = CType(objectSpace.GetObject(View.CurrentObject), Task)
        Dim detailView As DetailView = Application.CreateDetailView(objectSpace, task)
        detailView.ViewEditMode = ViewEditMode.Edit
        e.View = detailView
    End Sub
End Class

When you use a Data Access Mode that does not load real objects (ServerView, DataView, and InstantFeedbackView), use the IObjectSpace.Refresh method to reload a changed object in the current List View.