AssociationAttribute Classe

Définition

public ref class AssociationAttribute sealed : System::Data::Linq::Mapping::DataAttribute

[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple=false)]
public sealed class AssociationAttribute : System.Data.Linq.Mapping.DataAttribute

[<System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple=false)>]
type AssociationAttribute = class
    inherit DataAttribute

Public NotInheritable Class AssociationAttribute
Inherits DataAttribute

Héritage

Object

Attribute

DataAttribute

AssociationAttribute

Attributs

AttributeUsageAttribute

Exemples

private EntityRef<Customer> _Customer;
// ...
[Association(Name="FK_Orders_Customers", Storage="_Customer", ThisKey="CustomerID", IsForeignKey=true)]
public Customer Customer
{
    get
    {
        return this._Customer.Entity;
    }
    set
    {
        Customer previousValue = this._Customer.Entity;
        if (((previousValue != value)
                    || (!this._Customer.HasLoadedOrAssignedValue )))
        {
            this.SendPropertyChanging();
            if ((previousValue != null))
            {
                this._Customer.Entity = null;
                previousValue.Orders.Remove(this);
            }
            this._Customer.Entity = value;
            if ((value != null))
            {
                value.Orders.Add(this);
                this._CustomerID = value.CustomerID;
            }
            else
            {
                this._CustomerID = default(string);
            }
            this.SendPropertyChanged("Customer");
        }
    }
}

Private _Customer As EntityRef(Of Customer)
<Association(Name:="FK_Orders_Customers", Storage:="_Customer", ThisKey:="CustomerID", IsForeignKey:=True)>
Public Property Customer() As Customer
    Get
        Return Me._Customer.Entity
    End Get
    Set(ByVal value As Customer)
        Dim previousValue As Customer = Me._Customer.Entity
        If (((previousValue Is value) _
           = False) _
           OrElse (Me._Customer.HasLoadedOrAssignedValue = False)) Then
            Me.SendPropertyChanging()
            If ((previousValue Is Nothing) _
               = False) Then
                Me._Customer.Entity = Nothing
                previousValue.Orders.Remove(Me)
            End If
            Me._Customer.Entity = value
            If ((value Is Nothing) _
               = False) Then
                value.Orders.Add(Me)
                Me._CustomerID = value.CustomerID
            Else
                Me._CustomerID = CType(Nothing, String)
            End If
            Me.SendPropertyChanged("Customer")
        End If
    End Set
End Property

Remarques

Utilisez cet attribut pour représenter une association dans une base de données, telle que la relation entre une clé étrangère et une clé primaire.

Dans l’exemple suivant, la Order classe inclut un attribut permettant d’associer AssociationAttribute Orders à Customers.