ObjectChangedEventArgs.OldValue Property

Specifies the old value of a changed property.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

public object OldValue { get; }

VB.NET

Public ReadOnly Property OldValue As Object

Property Value

Type	Description
Object	The old value of a changed property.

Remarks

The IObjectSpace.ObjectChanged event can be triggered when an end-user starts modifying any property value in a UI. In this instance, the event is triggered, but the ObjectChangedEventArgs.NewValue and OldValue properties are equal. This is the designed behavior. So, if you want to execute a custom activity when a property value change occurs, check the equality of these properties preliminarily.

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the OldValue property.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

xaf-how-to-dynamically-change-mask-settings-based-on-the-current-object/CS/ChangeEditMask.Module/Controllers/ChangeMaskControllerBase.cs#L23

void ObjectSpace_ObjectChanged(object sender, ObjectChangedEventArgs e) {
    if (e.PropertyName == "Mask" && e.NewValue != e.OldValue) {
        UpdateMaskSettings();

VB.NET

xaf-how-to-dynamically-change-mask-settings-based-on-the-current-object/VB/ChangeEditMask.Module/Controllers/ChangeMaskControllerBase.vb#L23

Private Sub ObjectSpace_ObjectChanged(ByVal sender As Object, ByVal e As ObjectChangedEventArgs)
    If Equals(e.PropertyName, "Mask") AndAlso e.NewValue IsNot e.OldValue Then
        UpdateMaskSettings()