CollectionSourceModeAttribute Class

Specifies the mode of operation for the Collection Sources created by List Property Editors representing the CollectionSourceModeAttribute's target property.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v18.2.dll


[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, Inherited = true)]
public class CollectionSourceModeAttribute :
<AttributeUsage(AttributeTargets.Property Or AttributeTargets.Field, Inherited:=True)>
Public Class CollectionSourceModeAttribute
    Inherits Attribute
    Implements _Attribute

By default, collection properties are displayed by the ListPropertyEditor. This Property Editor presents a List View in a grid. You can specify in which mode a Collection Source for this List View will be created. To do this, apply the CollectionSourceMode attribute to the target collection property and pass a boolean value. This value will be set to the Collection Source's CollectionSourceBase.Mode property. There are two Collection Source modes: Normal and Proxy. In the Normal mode, the Collection Source's Object Space creates an XPCollection of objects of the specified type. In the Proxy mode, two collections are created: an original collection, as in the Normal mode, and an intermediate proxy collection. The proxy collection is the original collection's wrapper, initially required to support interfaces required for built-in XAF features. You can use the Proxy mode in the following scenario. If you filter the Collection Source's collection (e.g. using the Criteria Property of a List View's Collection Source), the CollectionSourceBase.Collection property will return a filtered collection. But in the Proxy mode, the filter is applied to the proxy collection. The original collection remains unfiltered and can be accessible. For details, refer to the CollectionSourceBase.Mode property description.

By default, the ListPropertyEditor creates a Collection Source in the Proxy mode. If you need to change this behavior with respect to a particular collection property, apply the CollectionSourceMode attribute to the property. If the source code of the property is not available, the attribute can be added in the following manner:

public override void CustomizeTypesInfo(ITypesInfo typesInfo) {
        new CollectionModeAttribute(CollectionSourceMode.Normal));

If you use a Server Mode for a nested List View, its Collection Source is created only in the Normal mode .



See Also