IObjectSpace.CustomCommitChanges Event

Replaces the default commit logic with a custom one.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

event EventHandler<HandledEventArgs> CustomCommitChanges

VB.NET

Event CustomCommitChanges As EventHandler(Of HandledEventArgs)

Event Data

The CustomCommitChanges event's data class is HandledEventArgs. The following properties provide information specific to this event:

Property	Description
Handled	Gets or sets a value that indicates whether the event handler has completely handled the event or whether the system should continue its own processing.

Remarks

The IObjectSpace.CommitChanges method call raises the CustomCommitChanges event. Handle this event to specify custom logic to commit persistent object changes. Set the CompletedEventArgs.Handled parameter to true to indicate that the commit operation is performed.

In the BaseObjectSpace descendant, the BaseObjectSpace.CommitChanges method invokes the BaseObjectSpace.DoCommit method and raises the CustomCommitChanges event. Override the BaseObjectSpace.DoCommit method to implement your logic to persist changes.

The following code shows how to manually save child collection changes made in the parent Detail View:

C#

using DevExpress.ExpressApp;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using YourSolutionName.Module.BusinessObjects;

namespace YourSolutionName.Module.Controllers {
    public class MyViewController : ObjectViewController<DetailView, Parent> {
        List<Child> detailObjectsCache = new List<Child>();
        protected override void OnActivated() {
            base.OnActivated();
            ObjectSpace.CustomCommitChanges += ObjectSpace_CustomCommitChanges;
            ObjectSpace.Committing += ObjectSpace_Committing;
            ObjectSpace.Committed += ObjectSpace_Committed;
            ObjectSpace.Reloaded += ObjectSpace_Reloaded;
        }
        protected override void OnDeactivated() {
            ObjectSpace.CustomCommitChanges -= ObjectSpace_CustomCommitChanges;
            ObjectSpace.Committing -= ObjectSpace_Committing;
            ObjectSpace.Committed -= ObjectSpace_Committed;
            ObjectSpace.Reloaded -= ObjectSpace_Reloaded;
            base.OnDeactivated();
        }
        void ObjectSpace_Reloaded(object sender, EventArgs e) {
            detailObjectsCache.Clear();
        }
        void ObjectSpace_Committed(object sender, EventArgs e) {
            detailObjectsCache.Clear();
        }
        void ObjectSpace_Committing(object sender, CancelEventArgs e) {
            IObjectSpace os = (IObjectSpace)sender;
            for (int i = os.ModifiedObjects.Count - 1; i >= 0; i--) {
                object item = os.ModifiedObjects[i];
                if (typeof(Child).IsAssignableFrom(item.GetType())) {
                    detailObjectsCache.Add(item as Child);
                    os.RemoveFromModifiedObjects(item);
                }
            }
        }
        void ObjectSpace_CustomCommitChanges(object sender, HandledEventArgs e) {
            // Implement custom logic to save Detail objects here. 
            foreach (Child detailObject in detailObjectsCache) {
                //...  
            }
        }
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports YourSolutionName.Module.BusinessObjects

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

        Private detailObjectsCache As List(Of Child) = New List(Of Child)()

        Protected Overrides Sub OnActivated()
            MyBase.OnActivated()
            AddHandler ObjectSpace.CustomCommitChanges, AddressOf ObjectSpace_CustomCommitChanges
            AddHandler ObjectSpace.Committing, AddressOf ObjectSpace_Committing
            AddHandler ObjectSpace.Committed, AddressOf ObjectSpace_Committed
            AddHandler ObjectSpace.Reloaded, AddressOf ObjectSpace_Reloaded
        End Sub

        Protected Overrides Sub OnDeactivated()
            RemoveHandler ObjectSpace.CustomCommitChanges, AddressOf ObjectSpace_CustomCommitChanges
            RemoveHandler ObjectSpace.Committing, AddressOf ObjectSpace_Committing
            RemoveHandler ObjectSpace.Committed, AddressOf ObjectSpace_Committed
            RemoveHandler ObjectSpace.Reloaded, AddressOf ObjectSpace_Reloaded
            MyBase.OnDeactivated()
        End Sub

        Private Sub ObjectSpace_Reloaded(ByVal sender As Object, ByVal e As EventArgs)
            detailObjectsCache.Clear()
        End Sub

        Private Sub ObjectSpace_Committed(ByVal sender As Object, ByVal e As EventArgs)
            detailObjectsCache.Clear()
        End Sub

        Private Sub ObjectSpace_Committing(ByVal sender As Object, ByVal e As CancelEventArgs)
            Dim os As IObjectSpace = CType(sender, IObjectSpace)

            For i As Integer = os.ModifiedObjects.Count - 1 To 0
                Dim item As Object = os.ModifiedObjects(i)

                If GetType(Child).IsAssignableFrom(item.[GetType]()) Then
                    detailObjectsCache.Add(TryCast(item, Child))
                    os.RemoveFromModifiedObjects(item)
                End If
            Next
        End Sub

        Private Sub ObjectSpace_CustomCommitChanges(ByVal sender As Object, ByVal e As HandledEventArgs)
            ' Implement custom logic to save Detail objects here.  
            For Each detailObject As Child In detailObjectsCache
            Next
        End Sub
    End Class
End Namespace