lazy loading 3

gistfile1.cs

[Serializable]
public sealed class LazyLoadAttribute : LocationInterceptionAspect
{
    public override void OnGetValue(LocationInterceptionArgs args)
    {
        var form = (ProductForm)args.Instance;  // this form is only used here to write to a listbox for demonstration

        args.ProceedGetValue();
        if (args.Value == null)
        {
            form.LogListBox.Items.Add("Instantiating ProductService");
            var locationType = args.Location.LocationType;
            var instantiation = ObjectFactory.GetInstance(locationType);

            if (instantiation != null)
            {
                args.SetNewValue(instantiation);
            }
        } else
        {
            form.LogListBox.Items.Add("Using a ProductService that has already been instantiated");
        }
        args.ProceedGetValue();
    }
}