BaseObjectSpace.ModifiedChanging Event
Occurs before the IsModified property is changed to true. Handle this event to cancel the property change or force the IsModified property to change.
Namespace: DevExpress.ExpressApp
Assembly: DevExpress.ExpressApp.v24.2.dll
NuGet Package: DevExpress.ExpressApp
#Declaration
public event EventHandler<ObjectSpaceModificationEventArgs> ModifiedChanging
#Event Data
The ModifiedChanging event's data class is ObjectSpaceModificationEventArgs. The following properties provide information specific to this event:
Property | Description |
---|---|
Cancel |
Specifies whether the Is |
Member |
Specifies an object that is information on the property whose value has been changed.
Inherited from Object |
New |
Specifies the new value of a changed property.
Inherited from Object |
Object |
Provides access to the object that is being manipulated.
Inherited from Object |
Old |
Specifies the old value of a changed property.
Inherited from Object |
Property |
Specifies the name of a property whose value has been changed. Returns null (Nothing in VB) if it is impossible to determine what property causes the change.
Inherited from Object |
#Remarks
The following example shows how to cancel the IsModified property change when you modify the Category property of a ProductView object. In this case, the current Object Space does not add this object to the ModifiedObjects collection.
File: MySolution.Blazor.Server/Startup.cs, MySolution.Win/Startup.cs, MySolution.WebApi/Startup.cs
using DevExpress.ExpressApp;
// ...
builder.ObjectSpaceProviders.Events.OnObjectSpaceCreated = context => {
var npos = context.ObjectSpace as NonPersistentObjectSpace;
if (npos != null) {
npos.ModifiedChanging += Npos_ModifiedChanging;
}
};
// ...
private void Npos_ModifiedChanging(object sender, ObjectSpaceModificationEventArgs e) {
if(e.MemberInfo!= null) {
if(e.MemberInfo.Owner.Type == typeof(ProductView) &&
e.MemberInfo.Name == nameof(ProductView.Category)) {
e.Cancel = true;
}
}
}
#Related GitHub Examples
The following code snippet (auto-collected from DevExpress Examples) contains a reference to the ModifiedChanging event.
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.