Session.FindObjectAsync<ClassType>(CriteriaOperator, AsyncFindObjectCallback) Method

Asynchronously searches for the first object which matches the specified criteria and has the type designated by the generic type parameter, and notifies upon completion.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v18.2.dll

Declaration

C#

public object FindObjectAsync<ClassType>(
    CriteriaOperator criteria,
    AsyncFindObjectCallback callback
)

VB.NET

Public Function FindObjectAsync(Of ClassType)(
    criteria As CriteriaOperator,
    callback As AsyncFindObjectCallback
) As Object

Parameters

Name	Type	Description
criteria	CriteriaOperator	A CriteriaOperator descendant which represents the criteria to match persistent objects.
callback	DevExpress.Xpo.Helpers.AsyncFindObjectCallback	A DevExpress.Xpo.Helpers.AsyncFindObjectCallback delegate to be called after the method completes. Use callback to do the following: Access the found object passed as the delegete’s result parameter, or store it for later use within the original thread. Store the exception information passed as delegete’s ex parameter, and use this information later to raise the exception again, within the original thread. Do not raise exceptions or modify persistent objects within a callback.

Type Parameters

Name
ClassType

Returns

Type	Description
Object	An object which represents the first persistent object matching the specified criteria. null (Nothing in Visual Basic) if no persistent object matching the criteria is found.

Remarks

Criteria are evaluated on the data store side. Objects created within a transaction (Cache), are not processed by the criteria. Objects modified within a transaction, are not processed. Instead, their images, stored in the data store, are processed by the criteria.

To specify how filter criteria are evaluated within a transaction, use the overloaded FindObjectAsync method that takes the PersistentCriteriaEvaluationBehavior value as a parameter.

Persistent objects that are marked as deleted in the database (see Deferred and Immediate Object Deletion) are not included in the search.