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Session.FindObjectAsync(XPClassInfo, CriteriaOperator, CancellationToken) Method

Asynchronously searches for the first object that matches the specified criteria.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v19.2.dll

Declaration

public Task<object> FindObjectAsync(
    XPClassInfo classInfo,
    CriteriaOperator criteria,
    CancellationToken cancellationToken = default(CancellationToken)
)
Public Function FindObjectAsync(
    classInfo As XPClassInfo,
    criteria As CriteriaOperator,
    cancellationToken As CancellationToken = Nothing
) As Task(Of Object)
public Task<object> FindObjectAsync(
    XPClassInfo classInfo,
    CriteriaOperator criteria,
    CancellationToken cancellationToken = default(CancellationToken)
)
Public Function FindObjectAsync(
    classInfo As XPClassInfo,
    criteria As CriteriaOperator,
    cancellationToken As CancellationToken = Nothing
) As Task(Of Object)

Parameters

Name Type Description
classInfo XPClassInfo

An XPClassInfo object which contains the metadata information. This data specifies which class needs to be searched.

criteria CriteriaOperator

A CriteriaOperator descendant which represents the criteria the persistent object must match.

cancellationToken CancellationToken

A CancellationToken object that delivers a cancellation notice to the running operation.

Parameters

Name Type Description
classInfo XPClassInfo

An XPClassInfo object which contains the metadata information. This data specifies which class needs to be searched.

criteria CriteriaOperator

A CriteriaOperator descendant which represents the criteria the persistent object must match.

cancellationToken CancellationToken

A CancellationToken object that delivers a cancellation notice to the running operation.

Returns

Type Description
Task<Object>

A Task that returns an object. This object represents the first persistent object that matches the specified criteria. null (Nothing in Visual Basic) if no persistent object is found that matches the criteria.

Returns

Type Description
Task<Object>

A Task that returns an object. This object represents the first persistent object that matches the specified criteria. null (Nothing in Visual Basic) if no persistent object is found that matches the criteria.

Remarks

The example below demonstrates how to use this method. Here, session is the Session instance.

using System.Threading;
using DevExpress.Data.Filtering;
using DevExpress.Xpo;
using DevExpress.Xpo.Metadata;
// ...
CancellationTokenSource source = new CancellationTokenSource();
CancellationToken cancellationToken = source.Token;
XPClassInfo personClassInfo = session.GetClassInfo(typeof(Person));
Person personToUpdate = (Person)await session.FindObjectAsync(personClassInfo,
    CriteriaOperator.Parse("Name='Michael Suyama'"), cancellationToken);
if(personToUpdate != null) {
    personToUpdate.Birthday = new DateTime(1986, 10, 31);
    session.Save(personToUpdate);
}

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

See Also