Using business logic callbacks

XData allows to use business logic callbacks to interact back-end modules with front-end using synchronous Callback and asynchronous PostData models. Synchronous calls can return result value. Callbacks can be used with three-tier-architecture as well as with client-server model. Callbacks has provided business logic clear, complete view and allows debug same code in two-tier environment as code will be executed in three-tier.

    public class InvoiceLogic : XDataLogic<Invoice>
    {
        public CustomLogic<Invoice> TestCustomLogic => (objects => {
            Log.Write(MessageType.Information, 
                () => $"TestCustomLogic called with {objects.Length} objects"); 
            foreach (var invoice in objects)
            {
                var i = invoice;
                invoice.PostData("testPost", () => Encoding.UTF8.GetBytes(i.DocNumb));
                var p = Encoding.UTF8.GetBytes(i.DocNumb);
                var r = i.Callback("testCall", ref p);
                Log.Write(MessageType.Information, () =>
                    @$"Call for \"{i.DocNumb}\" returned \"{r}\" with data 
\"{(p == null ? null : Encoding.UTF8.GetString(p))}\"");
            }
            return true;
        });
    }