AssociationAttribute Class

Identifies the end of an association that is involved in an object relationship.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v22.1.dll

Declaration

C#

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

VB.NET

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

Remarks

Apply this attribute to both properties at the ends of the association, specifying an object relationship.

Example

In the following sample code, the Location class might contain several Departments and each Department can in turn span several Locations.

C#

using DevExpress.Xpo;
// ...
public class Location : XPObject {
    public string Name {
        get { return fName; }
        set { SetPropertyValue(nameof(Name), ref fName, value); }
    }
    string fName;

    [Association("Locations-Departments")]
    public XPCollection<Department> Departments { 
        get { return GetCollection<Department>(nameof(Departments)); }
    }
}
public class Department : XPObject {
    public string Name {
        get { return fName; }
        set { SetPropertyValue(nameof(Name), ref fName, value); }
    }
    string fName;

    [Association("Locations-Departments")]
    public XPCollection<Location> Locations { 
        get { return GetCollection<Location>(nameof(Locations)); } 
    }
}

VB.NET

Imports DevExpress.Xpo
' ...
Public Class Location
    Inherits XPObject
    Public Property Name() As String
        Get
            Return fName
        End Get
        Set(ByVal value as String)
            SetPropertyValue(NameOf(Name), fName, value)
        End Set
    End Property
    Private fName As String

    <Association("Locations-Departments")> _
    Public ReadOnly Property Departments() As XPCollection(Of Department)
        Get
            Return GetCollection(Of Department)(NameOf(Departments))
        End Get
    End Property
End Class
Public Class Department
    Inherits XPObject
    Public Property Name() As String
        Get
            Return fName
        End Get
        Set(ByVal value as String)
            SetPropertyValue(NameOf(Name), fName, value)
        End Set
    End Property
    Private fName As String

    <Association("Locations-Departments")> _
    Public ReadOnly Property Locations() As XPCollection(Of Location)
        Get
            Return GetCollection(Of Location)(NameOf(Locations))
        End Get
    End Property
End Class

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the AssociationAttribute 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#

XPO_how-to-create-collection-properties-with-associations-at-runtime-e5139/CS/XPOConsoleApplication/Program.cs#L21

//A one-to-many association
XPMemberInfo miSupplier = ciProduct.CreateMember("Supplier", typeof(Supplier), new AssociationAttribute("SupplierProducts"));
XPMemberInfo miProducts = ciSupplier.CreateMember("Products", typeof(XPCollection), true, new AssociationAttribute("SupplierProducts", typeof(Product)));

XPO_how-to-create-persistent-classes-mapped-to-tables-with-a-composite-primary-key-at-runtime-e4606/CS/XpoConsoleApplication/Program.cs#L23

ciProject.CreateMember("Description", typeof(string), new SizeAttribute(SizeAttribute.Unlimited));
ciProject.CreateMember("Assignments", typeof(XPCollection), true, new AssociationAttribute("R1", null, "Assignment"));

XPO_how-to-generate-persistent-classes-at-runtime-based-on-a-dataset-e1198/CS/WindowsApplication4/Form1.cs#L48

XPClassInfo customer = CreateObject(s, "Customer", typeof(ParentDataObject));
AssociationAttribute a = new AssociationAttribute("CustomerOrders"); //, typeof(DetailDataObject)
a.ElementTypeName = "Order";

XPO_how-to-persist-metadata-e269/CS/MetadataObjects.cs#L164

public override Attribute Create() {
    return new AssociationAttribute(AssociationName, ElementAssemblyName, ElementTypeName);
}

VB.NET

XPO_how-to-create-collection-properties-with-associations-at-runtime-e5139/VB/XPOConsoleApplication/Program.vb#L21

'A one-to-many association
Dim miSupplier As XPMemberInfo = ciProduct.CreateMember("Supplier", GetType(Supplier), New AssociationAttribute("SupplierProducts"))
Dim miProducts As XPMemberInfo = ciSupplier.CreateMember("Products", GetType(XPCollection), True, New AssociationAttribute("SupplierProducts", GetType(Product)))

XPO_how-to-create-persistent-classes-mapped-to-tables-with-a-composite-primary-key-at-runtime-e4606/VB/XpoConsoleApplication/Program.vb#L23

ciProject.CreateMember("Description", GetType(String), New SizeAttribute(SizeAttribute.Unlimited))
ciProject.CreateMember("Assignments", GetType(XPCollection), True, New AssociationAttribute("R1", Nothing, "Assignment"))

XPO_how-to-generate-persistent-classes-at-runtime-based-on-a-dataset-e1198/VB/WindowsApplication4/Form1.vb#L46

Dim customer As XPClassInfo = CreateObject(s, "Customer", GetType(ParentDataObject))
Dim a As New AssociationAttribute("CustomerOrders") ', typeof(DetailDataObject)
a.ElementTypeName = "Order"

XPO_how-to-persist-metadata-e269/VB/MetadataObjects.vb#L255

Public Overrides Function Create() As Attribute
    Return New AssociationAttribute(AssociationName, ElementAssemblyName, ElementTypeName)
End Function

Inheritance

Object

Attribute

AssociationAttribute