CollectionSource Class
The Collection Source used for the List Views that display collections of business objects.
Namespace: DevExpress.ExpressApp
Assembly: DevExpress.ExpressApp.v24.2.dll
NuGet Package: DevExpress.ExpressApp
Declaration
Remarks
The CollectionSource is used by the root (see View.IsRoot) List Views. Generally, you can expect a List View to use the CollectionSource in the following cases:
A List View that is displayed in the XAF main window. In this case, the List View uses an instance of the CollectionSource class as its Collection Source.
A nested List View that displays a collection property uses the PropertyCollectionSource as the data source. However, the List View displayed in a pop-up Window invoked by the LinkUnlinkController.LinkAction uses the CollectionSource if the DataSourcePropertyAttribute is not applied to the collection property.
If the collection property has the DataSourcePropertyAttribute applied, the LookupEditPropertyCollectionSource is used instead.
To display a drop-down list of the possible values for a reference property, a Lookup Property Editor creates a List View. This List View uses an instance of the CollectionSource class as a data source if the DataSourcePropertyAttribute is not applied to the reference property.
If the reference property has the DataSourceProperty attribute applied, the LookupEditPropertyCollectionSource is used instead.
A CollectionSource instance is created in Client mode (the default setting), but you can set a DataView, Server, ServerView, InstantFeedback, InstantFeedbackView, or Queryable mode (see CollectionSourceBase.DataAccessMode) in the Application Model. In the Model Editor, navigate to the target List View node and set the IModelListView.DataAccessMode property to one of the CollectionSourceDataAccessMode enumeration values.
Note
If you want to create a Collection Source for a nested List View in Server, ServerView, InstantFeedback, InstantFeedbackView, or Queryable mode, make sure that there is no logic for sorting, filtering or something else in the collection’s getter, and there are no subscribers to the collection’s events. This logic and subscribers won’t be taken into account, because a standalone server collection will be created instead of the original one.
XAF automatically creates and manipulates a Collection Source when it creates a List View. However, the following typical tasks require you to instantiate or access a Collection Source manually:
- Create a custom List View. To be able to do it, you need to first create the required collection source.
- Filter a collection of objects that a List View displays on the data source level. To do this, you need to access the List View’s Collection Source (see Criteria Property of a List View’s Collection Source).