How to add a custom xDB facet to an IElementCollection facet

Question

I am implementing custom xDB facets in Sitecore 8.1-3. I have a facet called "Marketing Data". Most of the elements of "Marketing Data" are simple strings. I also have an element called "Shipping Addresses" that is a list of "Address" elements. It is unclear to me how to add a new element to the list. I see that the IElementCollection class has a Create method, but no Add method.

My Marketing Data facet interface looks like this

public interface IMarketingData : IFacet
{
    string Organization { get; set; }
    string Industries { get; set; }
    string ProductTypes { get; set; }
    IElementCollection<IAddress> ShippingAddresses { get; }
}

The implementation of Marketing Data looks like this

[Serializable]
public class MarketingData : Facet, IMarketingData
{
    private const string ORGANIZATION = "Organization";
    private const string INDUSTRIES = "Industries";
    private const string SHIPPINGADDRESSES = "ShippingAddresses";
    private const string PRODUCTTYPES = "ProductTypes";

    public string Organization
    {
        get { return GetAttribute<string>(ORGANIZATION); }
        set { SetAttribute(ORGANIZATION, value); }
    }

    public string Industries
    {
        get { return GetAttribute<string>(INDUSTRIES); }
        set { SetAttribute(INDUSTRIES, value); }
    }

    public IElementCollection<IAddress> ShippingAddresses
    {
        get { return GetCollection<IAddress>(SHIPPINGADDRESSES); }
    }

    public string ProductTypes
    {
        get { return GetAttribute<string>(PRODUCTTYPES); }
        set { SetAttribute(PRODUCTTYPES, value); }
    }

    public MarketingData()
    {
        EnsureAttribute<string>(ORGANIZATION);
        EnsureAttribute<string>(INDUSTRIES);
        EnsureCollection<IAddress>(SHIPPINGADDRESSES);
        EnsureAttribute<string>(PRODUCTTYPES);
    }
}

The interface for my address facet looks like this

public interface IAddress : IElement
{
    Guid Id { get; set; }
    string Company { get; set; }
    string Address1 { get; set; }
    string Address2 { get; set; }
    string City { get; set; }
    string Country { get; set; }
    string State { get; set; }
    string PostalCode { get; set; }
}

Then I have code where I want to add a new address to an existing contact. It looks like this

...code to get a contact from xDB and put it in lockedContact variable...

var marketingInfo = lockedContact.GetFacet<IMarketingData>("Marketing Data");

marketingInfo.Organization = txtOrganization.Text;
marketingInfo.Industries = txtIndustries.Text;
marketingInfo.ProductTypes = txtProductTypes.Text;

var newAddress = marketingInfo.ShippingAddresses.Create(); //Fails here
newAddress.Address1 = txtAddress1.Text;
newAddress.Address2 = txtAddress2.Text;
newAddress.City = txtCity.Text;
newAddress.State = txtState.Text;
newAddress.Country = txtCountry.Text;
newAddress.PostalCode = txtPostalCode.Text;
newAddress.Company = txtCompany.Text;

Am I using the Create method correctly? It doesn't seem like there is any way to pass an object in to the Create method so I am unsure how I would set the different address properties.

Answer 1

You need to register Address as your IAddress implementation in Sitecore configuration. You can see how it is done in Sitecore.Analytics.Model.config.

Basically, you'd have a patch file along the lines of:

<?xml version="1.0" encoding="utf-8"?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <model>
      <elements>
        <element
          interface="SomeNamespace.IAddress, SomeAssembly"
          implementation="SomeNamespace.Address, SomeAssembly" />
      </elements>
    </model>
  </sitecore>
</configuration>