AggregateOperand.Count(CriteriaOperator) Method

Creates a new AggregateOperand which returns the count of AggregateOperand.CollectionProperty elements that match the AggregateOperand.Condition.

Namespace: DevExpress.Data.Filtering

Assembly: DevExpress.Data.v24.1.dll

NuGet Package: DevExpress.Data

Declaration

C#

public AggregateOperand Count(
    CriteriaOperator aggregatedExpression
)

VB.NET

Public Function Count(
    aggregatedExpression As CriteriaOperator
) As AggregateOperand

Parameters

Name	Type	Description
aggregatedExpression	CriteriaOperator	A CriteriaOperator object which specifies the aggregate expression. This parameter may be ignored in certain circumstances.

Returns

Type	Description
AggregateOperand	An AggregateOperand object which calculates an aggregate expression.

Example

Get orders that have items with the IsAvailable property set to ‘True’.

Expression:

LINQ

CriteriaOperator.FromLambda<Order>(x => x.OrderItems.Count(i => i.IsAvailable == true) > 0);

Typed

var criterion = new AggregateOperand(nameof(Order.OrderItems), Aggregate.Count, new BinaryOperator(nameof(OrderItem.IsAvailable), true));
var resultCriterion = new BinaryOperator(criterion, 0, BinaryOperatorType.Greater);

String

CriteriaOperator.Parse("[OrderItems][IsAvailable=true].Count()>0");

Test

Input:

Order	OrderItem	IsAvailable
Order0
	Item0-0	False
	Item0-1	False
Order1
	Item1-0	True
	Item1-1	False
Order2
	Item2-0	False
	Item2-1	True

The result:

Order
Order1
Order2