Read.cs

public class ReadModelFacade : IReadModelFacade
{
    public IEnumerable<InventoryItemListDto> GetInventoryItems()
    {
        return FakeDatabase.list;
    }

    public InventoryItemDetailsDto GetInventoryItemDetails(Guid id)
    {
        return FakeDatabase.details[id];
    }
}

public class Details : PageModel
{
    public InventoryItemDetailsDto InventoryItem { get; set; }

    public void OnGet(string id)
    {
        InventoryItem = new ReadModelFacade().GetInventoryItemDetails(Guid.Parse(id));
    }
}