PersistentBase Class

Serves as a base for classes that represent persistent objects.

Assembly: DevExpress.Xpo.v23.2.dll

NuGet Packages: DevExpress.Win.PivotGrid, DevExpress.Win.TreeMap, DevExpress.Xpo

Declaration

C#
VB.NET

[NonPersistent]
[MemberDesignTimeVisibility(false)]
[OptimisticLocking(true)]
public class PersistentBase :
    IXPObject,
    IXPSimpleObject,
    IXPClassInfoAndSessionProvider,
    IXPClassInfoProvider,
    IXPDictionaryProvider,
    ISessionProvider,
    IObjectLayerProvider,
    IDataLayerProvider,
    IXPCustomPropertyStore,
    IXPModificationsStore,
    IXPInvalidateableObject,
    IXPReceiveOnChangedFromDelayedProperty,
    IXPReceiveOnChangedFromArbitrarySource,
    INotifyPropertyChanged,
    IXPImmutableHashCode

<NonPersistent>
<MemberDesignTimeVisibility(False)>
<OptimisticLocking(True)>
Public Class PersistentBase
    Implements IXPObject,
               IXPSimpleObject,
               IXPClassInfoAndSessionProvider,
               IXPClassInfoProvider,
               IXPDictionaryProvider,
               ISessionProvider,
               IObjectLayerProvider,
               IDataLayerProvider,
               IXPCustomPropertyStore,
               IXPModificationsStore,
               IXPInvalidateableObject,
               IXPReceiveOnChangedFromDelayedProperty,
               IXPReceiveOnChangedFromArbitrarySource,
               INotifyPropertyChanged,
               IXPImmutableHashCode

Remarks

The PersistentBase class provides the basic functionality required by persistent objects. It automatically supports the optimistic concurrency feature. If this feature is not required, you can use the XPLiteObject class instead.

When creating a persistent object by deriving from the PersistentBase, XPBaseObject, XPCustomObject or XPObject class, an OptimisticLockingAttribute is automatically applied to it. This attribute specifies whether a session can lock a persistent object’s state (allows optimistic locking to be enabled).

For more information, see XPObject and Optimistic Concurrency.

The following code demonstrates how to declare a persistent object.

C#
VB.NET

using DevExpress.Xpo;
using System.ComponentModel;

// Other base classes: https://docs.devexpress.com/eXpressAppFramework/113146/concepts/business-model-design/business-model-design-with-xpo/base-persistent-classes

public class MyClass : PersistentBase {
    public MyClass(Session session) : base(session) { }
    // PersistentBase does not have a built-in key and you need to add your own key
    [Key(AutoGenerate = true), Browsable(false)]
    public int Oid { get; set; }
    string fMyProperty;
    public string MyProperty {
        get { return fMyProperty; }
        set { SetPropertyValue(nameof(fMyProperty), ref fMyProperty, value); }
    }
}

Imports System.ComponentModel
Imports DevExpress.Xpo

' Other base classes: https://docs.devexpress.com/eXpressAppFramework/113146/concepts/business-model-design/business-model-design-with-xpo/base-persistent-classes

Public Class [MyClass]
    Inherits PersistentBase
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
    ' PersistentBase does not have a built-in key and you need to add your own key
    <Key(AutoGenerate:=True)>
    <Browsable(False)>
    Public Property Oid() As Integer
    Private fMyProperty As String
    Public Property MyProperty() As String
        Get
            Return fMyProperty
        End Get
        Set(ByVal value As String)
            SetPropertyValue(NameOf(MyProperty), fMyProperty, value)
        End Set
    End Property
End Class