CollectionSourceBase.Criteria Property

Provides access to the Collection Source’s CriteriaOperator dictionary that define the way in which the Collection Source’s CollectionSourceBase.Collection is filtered.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

public LightDictionary<string, CriteriaOperator> Criteria { get; }

VB.NET

Public ReadOnly Property Criteria As LightDictionary(Of String, CriteriaOperator)

Property Value

Type	Description
DevExpress.ExpressApp.Utils.LightDictionary<String, CriteriaOperator>	A LightDicationary of the CriteriaOperator objects that define the way in which the Collection Source’s CollectionSourceBase.Collection is filtered.

Remarks

To filter a Collection Source’s collection, add the required CriteriaOperators to the Criteria dictionary. No additional methods have to be called. The dictionary holds <String, CriteriaOperator> pairs. The String contains the description of a criterion and the CriteriaOperator denotes the criterion. The LightDictionary class implements the IDictionary interface. So, you can use its methods and properties - Add, Clear, Count, Remove and others.

When the content of the Criteria dictionary is changed, the Collection Source’s collection is filtered automatically. Two events are executed in the process - the CollectionSourceBase.CriteriaApplying and CollectionSourceBase.CriteriaApplied. Handle them to receive notifications when the Collection Source’s collection is filtered.

A persistent object used in Collection Source’s Criteria does not reload when the Object Space is refreshed, which raises the SessionMixingException exception. To avoid this, use a persistent object’s key property instead of the object itself.

C#

View.CollectionSource.Criteria["Filter1"] = CriteriaOperator.Parse("Manager.Oid = ?", ObjectSpace.GetKeyValue(manager));

VB.NET

View.CollectionSource.Criteria("Filter1") = CriteriaOperator.Parse("Manager.Oid = ?", ObjectSpace.GetKeyValue(manager))

The following topics contain examples on accessing and manipulating the Criteria dictionary:

• Criteria Property of a List View’s Collection Source
• How to: Use Criteria Property Editors

Note

• In nested List Views, the Criteria is not directly applied to the associated collection. Instead, a separate collection is created, and the criteria are applied to it; the original associated collection is not modified. A nested List View in the Client data access mode with a disabled proxy collection (see XafApplication.DefaultCollectionSourceMode) is an exception. In this instance, the criteria are directly applied to the associated collection.

• Currently, TreeListEditor has limited filtering capabilities. Only root tree nodes are filtered if you specify the Collection Source’s Criteria property when filtering the List View.

Related GitHub Examples

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

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#

XAF_how-to-create-a-custom-action-type-with-a-custom-control-barcheckitem-associated-with-it-e1977/CS/CustomActionControl.Module.Win/Controllers/SampleController.cs#L18

if (applyFilter){
    View.CollectionSource.Criteria["IsActive"] = new OperandProperty("Active");
} else {

XAF_how-to-use-criteria-property-editors-e932/CS/HowToUseCriteriaPropertyEditors.Module/CriteriaController.cs#L37

((ListView)View).CollectionSource.Criteria.Clear();
((ListView)View).CollectionSource.Criteria[e.SelectedChoiceActionItem.Caption] =
   CriteriaEditorHelper.GetCriteriaOperator(

xaf-how-to-create-a-custom-action-with-a-custom-control-in-xaf-aspnet-application/CS/Solution28.Module.Web/Controllers/ViewControllerWithParametrizedAction.cs#L15

    Range<DateTime> range = (Range<DateTime>)e.ParameterCurrentValue;
    ((ListView)View).CollectionSource.Criteria["By Date"] = CriteriaOperator.Parse("[Date] <= ? AND [Date] >= ?", range.To, range.From);
}

xaf-how-to-implement-dependent-views-in-a-dashboardview-filter-based-on-selection/CS/Solution3.Module/Controllers/DashboardFilterController.cs#L25

if(searchedObjects.Count > 0) {
    detailListView.CollectionSource.Criteria[CriteriaName] = new InOperator("Position.Oid", searchedObjects);
}

VB.NET

XAF_how-to-create-a-custom-action-type-with-a-custom-control-barcheckitem-associated-with-it-e1977/VB/CustomActionControl.Module.Win/Controllers/SampleController.vb#L20

If applyFilter Then
    View.CollectionSource.Criteria("IsActive") = New OperandProperty("Active")
Else

XAF_how-to-use-criteria-property-editors-e932/VB/HowToUseCriteriaPropertyEditors.Module/CriteriaController.vb#L38

CType(View, ListView).CollectionSource.Criteria.Clear()
CType(View, ListView).CollectionSource.Criteria(e.SelectedChoiceActionItem.Caption) = CriteriaEditorHelper.GetCriteriaOperator(TryCast(e.SelectedChoiceActionItem.Data, String), View.ObjectTypeInfo.Type, ObjectSpace)
CType(View, ListView).CollectionSource.EndUpdateCriteria()

xaf-how-to-create-a-custom-action-with-a-custom-control-in-xaf-aspnet-application/VB/Solution28.Module.Web/Controllers/ViewControllerWithParametrizedAction.vb#L17

    Dim range As Range(Of Date) = CType(e.ParameterCurrentValue, Range(Of Date))
    CType(View, ListView).CollectionSource.Criteria("By Date") = CriteriaOperator.Parse("[Date] <= ? AND [Date] >= ?", range.To, range.From)
End Sub

xaf-how-to-implement-dependent-views-in-a-dashboardview-filter-based-on-selection/VB/Solution3.Module/Controllers/DashboardFilterController.vb#L27

If searchedObjects.Count > 0 Then
    detailListView.CollectionSource.Criteria(CriteriaName) = New InOperator("Position.Oid", searchedObjects)
End If