Session.FindObjectAsync(XPClassInfo, CriteriaOperator, Boolean, AsyncFindObjectCallback) Method
Asynchronously searches for the first object which matches the specified criteria, and notifies upon completion.
Namespace: DevExpress.Xpo
Assembly: DevExpress.Xpo.v18.2.dll
Declaration
public object FindObjectAsync(
XPClassInfo classInfo,
CriteriaOperator criteria,
bool selectDeleted,
AsyncFindObjectCallback callback
)
Parameters
Name | Type | Description |
---|---|---|
classInfo | XPClassInfo | An XPClassInfo object which contains the metadata information of the class. |
criteria | CriteriaOperator | A CriteriaOperator descendant which represents the criteria to match persistent objects. |
selectDeleted | Boolean | true to include persistent objects marked for deletion into the search; otherwise, false. |
callback | DevExpress.Xpo.Helpers.AsyncFindObjectCallback | A DevExpress.Xpo.Helpers.AsyncFindObjectCallback delegate to be called after the method completes. Use callback to do the following:
Do not raise exceptions or modify persistent objects within a callback. |
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 can be optionally included in the search using the selectDeleted parameter.