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How can I use LazyLoading with WCF without causing circular references?
using MyModels;

public class ConsumerDataAccess
{
    public ConsumerModel GetConsumerById(int id)
    {
        ConsumerDTO dto = WCFService.GetConsumer(id);
        return new ConsumerModel(dto);
    }
}

public class ConsumerModel
{
    public ObservableCollection<PhoneNumberModel> _phoneNumbers;

    public ObservableCollection<PhoneNumberModel> PhoneNumbers
    {
        get
        {
            if (_phoneNumbers == null)
            {
                // Can't reference DataAccess Library since that would cause a Circular Reference
            }
        }
    }
}

public class ConsumerDataAccess
{
    public ConsumerModel GetConsumerById(int id)
    {
        ConsumerDTO dto = WCFService.GetConsumer(id);
        ConsumerModel rtnValue = new ConsumerModel(dto);
        ConsumerModel.LazyLoadData = LazyLoadConsumerData;
        return rtnValue;
    }
}

private object LazyLoadConsumerData(string key, object args)
{
    switch (key)
    {
        case "Phones":
            return PhoneDataAccess.GetByConsumerId((int)args);
        default:
            return null;
    }
}

public class ConsumerModel
{
    public delegate object LazyLoadDataDelegate(string id, object args);
    public LazyLoadDataDelegate LazyLoadData { get; set; }

    public ObservableCollection<PhoneNumberModel> _phoneNumbers;

    public ObservableCollection<PhoneNumberModel> PhoneNumbers
    {
        get
        {
            if (_phoneNumbers == null && LazyLoadData != null)
            {
                _phoneNumbers = (ObservableCollection<PhoneNumberModel>)
                        LazyLoadData("Phones", ConsumerId);
            }
            return _phoneNumbers;
        }
    }
}

public class LazyLoadEventArgs: EventArgs
{
    public object Data { get; set; }

    public string PropertyName { get; set; }

    public int Key { get; set; }
}

public event EventHandler<LazyLoadEventArgs> LazyLoadData;

public ObservableCollection<PhoneNumberModel> PhoneNumbers
{
    get
    {
        if (_phoneNumbers == null)
        {
            LazyLoadEventArgs args = new LazyLoadEventArgs {
                PropertyName = "PhoneNumbers",
                Key = this.Id
            };
            LazyLoadData(this, args);
            if (args.Data != null)
               this._phoneNumbers = args.Data as ObservableCollection<PhoneNumberModel>;
        }
        return _phoneNumbers;
    }
}

private void Model_HandleLazyLoadData(object sender, LazyLoadEventArgs e)
{
    switch (e.PropertyName)
    {
        case "PhoneNumbers":
            e.Data = DAL.LoadPhoneNumbers(e.Key);
            break;
        ...
    }
}