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AssociationAttribute Class

AssociationAttribute Class

Designates a property to represent a database association, such as a foreign key relationship.


Namespace:  System.Data.Linq.Mapping
Assembly:  System.Data.Linq (in System.Data.Linq.dll)

<AttributeUsageAttribute(AttributeTargets.Property Or AttributeTargets.Field, AllowMultiple := False)> _
Public NotInheritable Class AssociationAttribute _
	Inherits DataAttribute

The AssociationAttribute type exposes the following members.

Public methodAssociationAttributeInitializes a new instance of the AssociationAttribute class.

Public propertyDeleteOnNullWhen placed on a 1:1 association whose foreign key members are all non-nullable, deletes the object when the association is set to null.
Public propertyDeleteRuleGets or sets delete behavior for an association.
Public propertyIsForeignKeyGets or sets the member as the foreign key in an association representing a database relationship.
Public propertyIsUniqueGets or sets the indication of a uniqueness constraint on the foreign key.
Public propertyNameGets or sets the name of a column. (Inherited from DataAttribute.)
Public propertyOtherKeyGets or sets one or more members of the target entity class as key values on the other side of the association.
Public propertyStorageGets or sets a private storage field to hold the value from a column. (Inherited from DataAttribute.)
Public propertyThisKeyGets or sets members of this entity class to represent the key values on this side of the association.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)

Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

Use this attribute to represent an association in a database, such as the relationship between a foreign key and a primary key.

In the following example, the Order class includes an AssociationAttribute attribute to associate Orders with Customers.

Private _Customer As EntityRef(Of Customer)
<Association(Name:="FK_Orders_Customers", Storage:="_Customer", ThisKey:="CustomerID", IsForeignKey:=True)> _
Public Property Customer() As Customer
        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 
            If ((previousValue Is Nothing) _
               = False) Then 
                Me._Customer.Entity = Nothing
            End If 
            Me._Customer.Entity = value
            If ((value Is Nothing) _
               = False) Then
                Me._CustomerID = value.CustomerID
                Me._CustomerID = CType(Nothing, String)
            End If 
        End If 
    End Set 
End Property

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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