XPObject Class

Implements the IXPObject and provides an autogenerated integer key mapped to the ‘OID’ field.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v21.1.dll

Declaration

C#

[NonPersistent]
[MemberDesignTimeVisibility(false)]
public abstract class XPObject :
    XPCustomObject

VB.NET

<NonPersistent>
<MemberDesignTimeVisibility(False)>
Public MustInherit Class XPObject
    Inherits XPCustomObject

Remarks

Persistent objects are the objects that can be saved to and restored from a data store. Persistent objects represent the records in a table and encapsulate all the required relationships. The field values are represented as properties. Therefore a data table is merely represented by a collection of persistent objects. With eXpress Persistent Objects you will never have to deal with table mapping - all you need to do is to define persistent object classes, and XPO will automatically generate a database for them.

When creating a persistent object by deriving from the 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, Optimistic Concurrency.

The following code demonstrates how to declare a persistent object.

C#

using 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 : XPObject {
    // XPObject has a built-in Integer key and you can't add a custom key
    public MyClass(Session session) : base(session) { }
    string fMyProperty;
    public string MyProperty {
        get { return fMyProperty; }
        set { SetPropertyValue(nameof(fMyProperty), ref fMyProperty, value); }
    }
}

VB.NET

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 XPObject
    ' XPObject has a built-in Integer key and you can't add a custom key
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
    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

Concepts

• XPO Classes Comparison
• Create a Persistent Object
• Saving Persistent Objects
• Deleting Persistent Objects
• Validating Objects
• Basics of Creating Persistent Objects for Existing Data Tables
• Generating Persistent Objects for Existing Data Tables

Task-Based Help

• How to: Create an Aggregated Object
• How to: Handle Persistent Object Initialization
• How to: Prevent Changes in a Persistent Object from being Automatically Committed

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the XPObject class.

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#

how-to-use-dxgrid-in-server-mode-with-xpo-e1861/CS/XpoNorthwindServerMode/NorthwindXpo.cs#L8

public class Employee : XPObject {
    public Employee(Session session) : base(session) { }

wpf-data-grid-in-server-mode-with-xpo/CS/XpoNorthwindServerMode/NorthwindXpo.cs#L8

public class Employee : XPObject {
    public Employee(Session session) : base(session) { }

XPO_how-to-create-collection-properties-with-associations-at-runtime-e5139/CS/XPOConsoleApplication/Program.cs#L67

public class Supplier : XPObject {
    public Supplier(Session session) : base(session) { }

XPO_how-to-persist-metadata-e269/CS/MetadataObjects.cs#L9

[NonPersistent]
public class MyBaseObject : XPObject {
    public MyBaseObject(Session session, XPClassInfo classInfo) : base(session, classInfo) { }

how-to-use-two-grid-controls-to-display-one-to-many-relationship-e798/CS/PersistentObjects.cs#L5

public class Customer : XPObject {
    public string Name;

VB.NET

how-to-use-dxgrid-in-server-mode-with-xpo-e1861/VB/XpoNorthwindServerMode/NorthwindXpo.vb#L6

Public Class Employee
    Inherits XPObject

wpf-data-grid-in-server-mode-with-xpo/VB/XpoNorthwindServerMode/NorthwindXpo.vb#L6

Public Class Employee
    Inherits XPObject

XPO_how-to-create-collection-properties-with-associations-at-runtime-e5139/VB/XPOConsoleApplication/Program.vb#L83

Public Class Supplier
    Inherits XPObject

XPO_how-to-persist-metadata-e269/VB/MetadataObjects.vb#L10

Public Class MyBaseObject
    Inherits XPObject

how-to-use-two-grid-controls-to-display-one-to-many-relationship-e798/VB/PersistentObjects.vb#L7

Public Class Customer
    Inherits XPObject
    Public Name As String

Implements

IXPObject

IXPSimpleObject

ISessionProvider

IXPModificationsStore

Inheritance

Object

PersistentBase

XPBaseObject

XPCustomObject

XPObject

DCIntermediateObject

XtraReportData