XAF : Implement Many-to-Many Relationship

The following code snippet shows Many-to-Many Relationship between DemoTask and Contact business classes objects.

DemoTask Class:

   1:  Public Class DemoTask

   2:      Inherits Task

   3:      Public Sub New(ByVal session As Session)

   4:          MyBase.New(session)

   5:      End Sub

   6:      <Association("Contact-DemoTask", GetType(Contact))> _

   7:      Public ReadOnly Property Contacts() As XPCollection

   8:          Get

   9:              Return GetCollection("Contacts")

  10:          End Get

  11:      End Property

  12:  End Class

  13:   

  14:   

• The Association attribute is applied to the XPCollection type Contacts property, representing the collection of associated Contacts.
• The Association attribute is required when setting a relationship between objects
• The GetCollection method is used to return a collection in Contacts property getter implementation.

Contact Class:

   1:  Public Class Contact

   2:      Inherits Person

   3:      '...

   4:      <Association("Contact-DemoTask", GetType(DemoTask))> _

   5:      Public ReadOnly Property Tasks() As XPCollection

   6:          Get

   7:              Return GetCollection("Tasks")

   8:          End Get

   9:      End Property

  10:  End Class

With the code above, necessary intermediate tables and relationships will be generated automatically.

[eXpressApp Framework]