CODE Framework: Writing MVVM/MVC WPF Applications

The CODE Framework is an open-source application framework by the makers of CODE Magazine. It is entirely free of charge. It covers a wide range of features that can be applied altogether or individually in an À la carte fashion. All of these features revolve around a single concept: Building advanced business applications in a productive and maintainable fashion while maintaining great application architecture. In this article, we are focusing on a subset of the CODE Framework, specifically the components used to build WPF applications using the MVVM and MVC patterns.

“Why another framework?” you may ask. After all, there are quite a few frameworks out there already. So why would a company like EPS and CODE Consulting (the same company that owns CODE Magazine) go through the effort of creating another framework? Well, for one, large parts of this framework have been around for quite some time and have been sold as part of a bigger commercial solution platform. So while the “CODE Framework” initiative is relatively new, much of the code this framework is based on is quite solid and has been around for a while (some parts more so than others). But the more important reason is that we felt we had something unique and important to contribute! While there is a lot of great stuff going on in Microsoft development communities, we feel it is simply too difficult to wield many of the great techniques and technologies. When looking at our own consulting and custom software customers, as well as what we saw at the many events and training classes we are involved with, and all the feedback we get from CODE Magazine readers, a common pattern seems to emerge. Let’s see if this sounds familiar: “You are either building an application or you are looking into frameworks and architecture for your next project, and you find tons of great stuff. But somehow, it all seems a bit complicated, especially if your project is a Windows project. So you get up and running and you are using amazing things and feel your architecture is real solid. But still, somehow it remains too difficult and progress is too slow. Only the best team members can work on the project (and they are clearly disgusted with the inability and lack of skill of everyone else) and even they are not managing to put things out as fast as you’d think. And at the end of the day the system seems a lot less flexible and maintainable than you’d expect, but you feel it is probably just your lack of your own knowledge when it comes to the details of the architecture and implementation.” Does that ring any bells?

Making Things Simpler, More Productive, and Unified

The reality is that we have reached a point with Microsoft technologies, where we have found amazing solutions to many problems. We can now create systems with better features than ever before, and we have amazing techniques for things such as testing and many other aspects of software projects. All these techniques are useful and worth learning, so you can apply them when you face certain problems.

We feel that the time has now come to make it simpler to apply many of these techniques!

We also feel that especially in the world of Windows development (be that current Windows technologies, or be that Windows 8 and its new Metro development environment) things are somewhat out of hand and there is no single skills-path people can take. If you are a Microsoft Web developer, you have one or two clear approaches you can take. You can become a Web Forms developer, or you can become an ASP.NET MVC developer. The latter being a very common choice these days. When you choose ASP.NET MVC, you have a very clear learning path ahead of you. It is well-understood and documented how ASP.NET MVC applications work. So you can learn that and then start working on ASP.NET MVC projects. You can also hire other ASP.NET MVC developers and expect that they have a similar level of knowledge. They will know how an ASP.NET MVC project is structured and they will have a good idea of how things flow and work together. (And if they do not, you can always make them read a book and they will arrive at that same level of knowledge.)

In Windows (and by extension, Silverlight) on the other hand, things are a bit different. The problem starts with people being quite vague on what technology to even use for Windows applications. But let’s assume for now that people have advanced far enough to use one of the XAML-based technologies. Even then, what is the common set of knowledge? It seems that the industry has now come to a point where “having a view model in the mix” is fairly widely accepted, bringing us to some incarnation of the MVVM pattern. But that is where the commonalities end.

There now are tons of frameworks that implement MVVM in different ways, each of them varying greatly in approach and implementation. There is no single set of knowledge a WPF developer can learn that is in any way similar to how an ASP.NET MVC developer could approach things. You may be learning Microsoft’s PRISM approach, but then how many people in the industry are there that have made the same learning effort? What are the chances that you will move onto your next project and it uses that framework, or what are the chances you will hire a developer off the street who happens to know PRISM? (Or substitute any other framework of your choice here.) The reality is: That chance is fairly slim. And even if they do, their interpretation of that framework may vary widely. Not to mention that all this brings us right back around to the fact that many of these frameworks remain difficult to use.

So looking at this situation, I feel strongly that this needs fixing. But how do we best approach this? I believe that WPF applications (or any other XAML or Windows technology for that matter) should not vary widely from other UI implementations. After all, why would the middle tier or the back end of an application change, just because you use a certain UI technology? I also feel that you should pick an approach that is known to work very well and is widely understood. In the world of .NET (and even beyond), one such approach is MVC. When you look at MVVM and MVC patterns, they have many things in common. Sure, there are some things that are different but the big picture items remain the same. We have UI definitions (views), we have models specific to those views that generally get populated from elsewhere, and in the MVC world, we have controllers that bring it all together and provide a starting point (an aspect that is sorely lacking in many MVVM implementations).

One feature of the CODE Framework is the ability to set up WPF projects using the same patterns as ASP.NET MVC applications. If you create a new WPF application using a CODE Framework template, you end up with a project setup that is practically identical to ASP.NET MVC. In fact, you could copy a lot of ASP.NET MVC code into your CODE Framework MVVM/MVC project and it will likely just work. It will also allow you to move ASP.NET MVC developers onto your project and they will become productive very quickly. (Of course their views are going to be defined in XAML not HTML, but more about that below.) And, as ASP.NET MVC has demonstrated, this overall setup is relatively easy to understand. Sure, the fact that there is a Controllers folder with classes that act as the starting point for just about anything may not be the most intuitive thing initially, but it is easy to learn. “If you are lost, look in the Controllers folder and add a breakpoint” is just about all a developer needs to know to get going. From that point forward, developers can step through the code and follow the flow to see what is going on. This basic ability is often completely absent from many MVVM projects. Techniques such as “inversion of control” are very useful, but they need to be applied in skillful ways, because their downside is that - as the name implies - they turn people’s worlds upside down. At that point, it becomes extremely difficult to follow what an application does. It is the easiest way to completely kill developer productivity.

Note: One of the core mantras in the CODE Framework is to make all features and techniques optional. If you find a certain approach or component useful, then go ahead and use it! But you can always skip the parts you do not like. And you can mix and match CODE Framework components freely with other frameworks. After all, there is no need to re-invent the things that already work well.

By: Markus Egger

Markus is an international speaker, having presented sessions at numerous conferences in North & South America and Europe. Markus has written many articles for publications including CoDe Magazine, Visual Studio Magazine, MSDN Brazil, asp.net Pro, FoxPro Advisor, Fuchs, FoxTalk and Microsoft Office and Database Journal. Markus is the publisher of CODE Magazine.

Markus is also the President and Chief Software Architect of EPS Software Corp., a custom software development and consulting firm located Houston, Texas. He specializes in consulting for object-oriented development, Internet development, B2B, and Web Services. EPS does most of development using Microsoft Visual Studio (.NET). EPS has worked on software projects for Fortune 500 companies including Philip Morris, Qualcomm, Shell, and Microsoft. Markus has also worked as a contractor on the Microsoft Visual Studio team, where he was mostly responsible for object modeling and other object- and component-related technologies.

Markus is a Microsoft RD and has continually received the Microsoft MVP Award since 1996 for his contributions to the developer community. Visual LandPro, one of the applications Markus was responsible for, was nominated three times in the Microsoft Excellence Awards.

megger@eps-software.com

Free but Supported!

CODE Framework is free. Period. You will never be asked to upgrade to a larger version or pay for any part of the source code, or anything of that nature.

We are also aware that while free is good, many organizations are somewhat concerned when free code is used “as is.” For those, CODE Consulting (our consulting arm) offers paid premium support, and CODE Training (you guessed it: our training division!) offers training classes.

For more information, contact info@codemag.com.