EntityInstantFeedbackSource.KeyExpression Property

Specifies the name of the key property.

Namespace: DevExpress.Data.Linq

Assembly: DevExpress.Data.v19.1.dll

Declaration

C#

[DefaultValue("")]
public string KeyExpression { get; set; }

VB.NET

<DefaultValue("")>
Public Property KeyExpression As String

Property Value

Type	Default	Description
String	String.Empty	A String value that specifies the key property name.

Remarks

Usually, the KeyExpression property specifies the name of the property mapped to the primary key column in the database.

You can modify the KeyExpression property value within the EntityInstantFeedbackSource.GetQueryable event handler, via the GetQueryableEventArgs.KeyExpression property.

To specify multiple columns of a composite key, pass the comma-separated or semicolon separated list of key column names to this property. For instance: “KeyPart1;KeyPart2;KeyPart3“.

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the KeyExpression property.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

mvvmexpenses-sample-application-t254492/CS/MVVMExpenses/Common/DataModel/EntityFramework/DbUnitOfWorkFactory.cs#L36

var source = new EntityInstantFeedbackSource((GetQueryableEventArgs e) => e.QueryableSource = projection(getRepositoryFunc(createUnitOfWork()))) {
    KeyExpression = getRepositoryFunc(createUnitOfWork()).GetPrimaryKeyPropertyName(),
};

VB.NET

mvvmexpenses-sample-application-t254492/VB/MVVMExpenses/Common/DataModel/EntityFramework/DbUnitOfWorkFactory.vb#L30

End If
Dim source = New EntityInstantFeedbackSource(Sub(e As GetQueryableEventArgs) e.QueryableSource = projection(getRepositoryFunc(_createUnitOfWork()))) With {.KeyExpression = getRepositoryFunc(_createUnitOfWork()).GetPrimaryKeyPropertyName()}
Return New InstantFeedbackSource(Of TProjection)(source, threadSafeProperties)