DataSourcePropertyAttribute.DataSourcePropertyIsNullMode Property

Specifies the Lookup Property Editor’s data source, in case the collection property specified by the DataSourcePropertyAttribute.DataSourceProperty is set to null (Nothing in VB).

Namespace: DevExpress.Persistent.Base

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

public DataSourcePropertyIsNullMode DataSourcePropertyIsNullMode { get; }

VB.NET

Public ReadOnly Property DataSourcePropertyIsNullMode As DataSourcePropertyIsNullMode

Property Value

Type	Description
DataSourcePropertyIsNullMode	A DataSourcePropertyIsNullMode enumeration value that specifies the Lookup Property Editor’s data source.

Available values:

Name	Description
SelectNothing	Specifies that the property’s Lookup List View is bound to an empty collection.
SelectAll	Specifies that the property’s Lookup List View is bound to a collection of all existing persistent objects of the property’s type.
CustomCriteria	Specifies that the Lookup List View is bound to a collection containing the objects that satisfy the criteria. The criteria should be specified by the DataSourcePropertyAttribute.DataSourcePropertyIsNullCriteria parameter of the DataSourcePropertyAttribute.

Remarks

You can change the DataSourcePropertyIsNullMode‘s value specified in code via the BOModel | <Class> | OwnMembers | <Member> node’s IModelCommonMemberViewItem.DataSourcePropertyIsNullMode property in the Model Editor.

To learn how to specify the Lookup Property Editor’s data source via the DataSourcePropertyAttribute, refer to the How to: Implement Cascading Filtering for Lookup List Views topic.