Session.EvaluateAsync(XPClassInfo, CriteriaOperator, CriteriaOperator, CancellationToken) Method
Asynchronously evaluates the specified expression against objects of the specified type.
Namespace: DevExpress.Xpo
Assembly: DevExpress.Xpo.v24.2.dll
NuGet Package: DevExpress.Xpo
#Declaration
public Task<object> EvaluateAsync(
XPClassInfo classInfo,
CriteriaOperator expression,
CriteriaOperator criteria,
CancellationToken cancellationToken = default(CancellationToken)
)
#Parameters
Name | Type | Description |
---|---|---|
class |
XPClass |
An XPClass |
expression | Criteria |
A Criteria |
criteria | Criteria |
A Criteria |
#Optional Parameters
Name | Type | Default | Description |
---|---|---|---|
cancellation |
Cancellation |
null | A Cancellation |
#Returns
Type | Description |
---|---|
Task<Object> | A Task that returns a value. This value is the evaluation’s result. |
#Remarks
Use this method to evaluate a specific expression against specific objects. You can pass functions specified by the Aggregate enumeration or you can pass a combination of these functions to the expression parameter. For example, you can use the “Count()” function to calculate the number of objects. The criteria parameter specifies the criteria used for object selection. The expression is evaluated only against objects that match these criteria. Set the criteria to null to evaluate the expression against all objects in the data store.
You can use the CriteriaOperator.Parse method to construct the expression and criteria. This method takes a string representation of the required expression and retrieves a CriteriaOperator object that corresponds to this expression.