XPBaseCollection.CollectionChanged Event

Occurs when an item is added to, or removed from the XPBaseCollection (when the XPBaseCollection.BaseAdd or XPBaseCollection.BaseRemove method is called).

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v19.2.dll

Declaration

C#

public event XPCollectionChangedEventHandler CollectionChanged

VB.NET

Public Event CollectionChanged As XPCollectionChangedEventHandler

Event Data

The CollectionChanged event's data class is XPCollectionChangedEventArgs.

Remarks

To subscribe to this event, override the XPBaseObject.CreateCollection<T> or PersistentBase.CreateCollection method of your persistent class.

C#

// Example for generic collection:
protected override XPCollection<T> CreateCollection<T>(XPMemberInfo property) {
    XPCollection<T> collection = base.CreateCollection<T>(property);
    if (property.Name == "MyGenericCollectionProperty") {
        collection.CollectionChanged += collection_CollectionChanged;
    }
    return collection;
}
// Example for non-generic collection:
protected override XPCollection CreateCollection(XPMemberInfo property) {
    XPCollection collection = base.CreateCollection(property);
    if (property.Name == "MyCollectionProperty") {
        collection.CollectionChanged += collection_CollectionChanged;
    }
    return collection;
}

VB.NET

' Example for generic collection:
Protected Overrides Function CreateCollection(Of T)(ByVal [property] As XPMemberInfo) As XPCollection(Of T)
    Dim collection As XPCollection(Of T) = MyBase.CreateCollection(Of T)([property])
    If [property].Name = "MyGenericCollectionProperty" Then
        AddHandler collection.CollectionChanged, AddressOf collection_CollectionChanged
    End If
    Return collection
End Function
' Example for non-generic collection:
Protected Overrides Function CreateCollection(ByVal [property] As XPMemberInfo) As XPCollection
    Dim collection As XPCollection = MyBase.CreateCollection([property])
    If [property].Name = "MyCollectionProperty" Then
        AddHandler collection.CollectionChanged, AddressOf collection_CollectionChanged
    End If
    Return collection
End Function

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the CollectionChanged 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.

C#

XPO_how-to-implement-a-calculated-property-aggregating-collection-items-e1477/CS/DetailCollectionChanged/DataObjects.cs#L23

if(property.Name == "Children")
    col.CollectionChanged += new XPCollectionChangedEventHandler(col_CollectionChanged);
return col;

XAF_how-to-show-the-grandchildren-collection-in-the-detailview-e1448/CS/WinSample.Module/Master.cs#L45

if (property.Name == "Details") {
    collection.CollectionChanged += new XPCollectionChangedEventHandler(Details_CollectionChanged);
}

VB.NET

XPO_how-to-implement-a-calculated-property-aggregating-collection-items-e1477/VB/DetailCollectionChanged/DataObjects.vb#L27

If [property].Name = "Children" Then
    AddHandler col.CollectionChanged, AddressOf col_CollectionChanged
End If

XAF_how-to-show-the-grandchildren-collection-in-the-detailview-e1448/VB/WinSample.Module/Master.vb#L53

If [property].Name = "Details" Then
    AddHandler collection.CollectionChanged, AddressOf Details_CollectionChanged
End If