How to: Link Classes Located in Different Assemblies

• Aug 24, 2020

If you have access to the sources of the classes to be linked, use the AssociationAttribute with the AssociationAttribute.AssemblyName and AssociationAttribute.ElementTypeName as follows:

C#

[Association("CustomersOrderLink", "CustomerAssembly", "CustomerAssembly.Customer")]
public Customer.Customer Customer { get; set; }
// ...
[Association("CustomersOrderLink", "OrderAssembly", "OrderAssembly.Order")]
public XPCollection Orders { get; }

VB.NET

<Association("CustomersOrderLink", "CustomerAssembly", "CustomerAssembly.Customer")> _
Public Property Customer() As Customer.Customer
' ...
Public Class XpObject
<Association("CustomersOrderLink", "OrderAssembly", "OrderAssembly.Order")> _
Public ReadOnly Property Orders() As XPCollection
End Class

When you cannot modify the sources of the classes to be linked, you can introduce an intermediate class:

C#

public class CustomerToOrderLink {
    public Customer Customer;
    public Order Order;
}

VB.NET

Public Class CustomerToOrderLink 
   Public Customer As Customer
   Public Order As Order
End Class

Or, define an association dynamically at runtime, using the XPClassInfo.CreateMember method.

C#

XPClassInfo customerInfo = dictionary.GetClassInfo(typeof(Customer));
XPClassInfo orderInfo = dictionary.GetClassInfo(typeof(Order));
customerInfo.CreateMember("Orders", typeof(XPCollection<Order>), true, false, new AssociationAttribute("Customer-Orders", typeof(Order)));
orderInfo.CreateMember("Customer", customerInfo, new AssociationAttribute("Customer-Orders"));

VB.NET

Dim customerInfo As XPClassInfo = dictionary.GetClassInfo(GetType(Customer))
Dim orderInfo As XPClassInfo = dictionary.GetClassInfo(GetType(Order))
customerInfo.CreateMember("Orders", GetType(XPCollection(Of Order)), True, False, New AssociationAttribute("Customer-Orders", GetType(Order)))
orderInfo.CreateMember("Customer", customerInfo, New AssociationAttribute("Customer-Orders"))