On Fri, Dec 1, 2017 at 5:43 PM, Graeme Geldenhuys via Lazarus <lazarus@lists.lazarus-ide.org> wrote: > On 2017-12-01 13:33, Marcos Douglas B. Santos via Lazarus wrote: >> >> I believe RAD is the best way to code a GUI.... > > > I'll even disagree with that - somewhat. :) > > http://geldenhuys.co.uk/articles/model-gui-mediator.pdf > > With Model-GUI-Mediator (think MVC or MVP design patterns but for modern GUI > toolkits) you use RAD style to drop components on a form, but you DON'T hook > into any events or Dataset properties using the form designer. Also, you > DON'T use data-aware controls.
I am aware of MVC, MVP, MVVM, and now MGM. I agree with you but, they represent almost the same thing. > Instead you use Mediators - a very thin layer of non-gui code (reusable and > only implemented once) that links widgets and business objects. > Bi-directional updates occur automatically via the Objserver design pattern. > MGM was the reason FPC now has Observers built into classes like TStringList > etc. Unfortunately, it was implemented in a wrong way, using classes instead of interfaces instances. > The MGM implementation I described in the article is very basic - to get the > idea across much easier. The MGM implementation inside tiOPF is *much* more > advanced and improved - requiring *much* less boiler-plate coding too. > > MGM also allows you to switch your application from LCL to fpGUI to VCL in a > blink of an eye. The mediators for all these toolkits are already written - > so nothing new to implement. Switching a form design from using a TListView > to TStringGrid (or vice-versa) is also a 2 second job. That is interesting. > Creating mediators for new components....For example TChart ora DevExpress > QuantumGrid is a 5 minute job at most. So suddenly you can use any of the > free or paid for components - not just db-aware components. > > I've used MGM in multiple commercial projects for about 6 years now - it > works brilliantly. You UI form units are almost empty, and good separation > of UI, business rules and persistence. Plus I can use OOP and real "objects" > in my code, not SQL queries and TField instances. I think you misunderstand me. I said "RAD is the best way to code a GUI", the visual part, not the business rules. I don't use db-aware — well only TDBGrid just to show data — and I don't have any business rules using TFields, Before|After Post, etc. Best regards, Marcos Douglas -- _______________________________________________ Lazarus mailing list Lazarus@lists.lazarus-ide.org https://lists.lazarus-ide.org/listinfo/lazarus
