On 10/11/2007, Al Boldi <[EMAIL PROTECTED]> wrote: > > This is a big misconception. The fact that TForm has the ability to host > business rules and whatever else does not mean that you have to do it this > way. You can maintain whatever model you like with TForm, for the mere fact > that it's event-driven.
And that's where the problem comes in. Borland gave developers DB-Aware components with all these great events to hook into. They simply guide the developer into adding code into the forms, mixing business rules with the presentation layer. I've maintained enough Delphi code from multiple projects in my career and every app designed with DB-Aware components have business rules embedded in the forms. >From specific filters to calculated fields, hard coded SQL etc... Not to mention all these DB-Aware components tie you into a specify database structure due to hard coded field names used in the components + tying you to a specific component vendor. DB-Aware components are great for quick prototyping, but that's about it. But hey, this is a totally separate topic that can go on forever.... OPF's vs DB-Aware components. > Yes, if your requirements are such that they call for a disconnected > presentation layer, then you have a case to use an MVP. Business rules should *always* be disconnected from the presentation layer! They are separate layers to start with. > the presentation layer. You don't have to use this layer if you don't like > to, and you could conceivably create a disconnected model based on TForms Yes it might be possible, but in my career I am still waiting to see a DB-Aware based application where the layers are neatly separated. > > Sounds interesting. Does it feature a WebPresentation proxy? Mediators are very easy to implement. Unfortunately I cannot share more code than I have in the tiOPF project due to IP held by my employer. My MGM implementation as show in tiOPF uses RTTI extensively so is slightly different to the design mentioned in Andy's article. The end result is the same. To me, MGM sits somewhere between MVC and MVP. A nice middle ground and very easy to implement. Regards, - Graeme - _______________________________________________ fpGUI - a cross-platform Free Pascal GUI toolkit http://opensoft.homeip.net/fpgui/ _________________________________________________________________ To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
