KeyAttribute Class

Indicates that a property or a field is a key.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v18.2.dll

Declaration

C#

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, Inherited = true)]
public sealed class KeyAttribute :
    Attribute

VB.NET

<AttributeUsage(AttributeTargets.Property Or AttributeTargets.Field, Inherited:=True)>
Public NotInheritable Class KeyAttribute
    Inherits Attribute

Remarks

Apply this attribute to a property or a field to mark it as a key. The KeyAttribute.AutoGenerate property specifies whether the key is generated automatically.

Note

When a key is changed for a saved object, XPO considers this object as new and inserts a new record into the database. Key properties must not be changed once a persistent object is saved. An end-user must never be allowed to change an object’s key property. We recommend that you define a key property as “read-only”.

C#

[Key(true), Persistent("CategoryID")]
int fCategoryID = -1;

[PersistentAlias("fCategoryID")]
public int CategoryID {
    get { return fCategoryID; }
}

VB.NET

<Key(True), Persistent("CategoryID")> _
Private fCategoryID As Integer = -1

<PersistentAlias("fCategoryID")> _
Public ReadOnly Property CategoryID() As Integer
    Get
        Return fCategoryID
    End Get
End Property

Inheritance

Object

Attribute

KeyAttribute