Is there a preferred practice to do Data Validation from within your ViewModel?
Looking into it some people seem to prefer IDataErrorInfo and some prefer to roll out their own validation frameworks (http://www.codeproject.com/KB/WPF/wpf_custom_validation.aspx)?
I'm wondering what the "Best Practice" is for Data Validation? Is there something that is accepted by the community when it comes to adhering to the M-V-VM guidelines?
Oh, and an FYI, I'm using Prism as my MVVM framework, but I don't think it has any laid out code for Validation assistance.
You might use the Validation Framework of the .NET Framework. It can be used with PRISM or any other MVVM Framework. The BookLibrary sample application of the WPF Application Framework (WAF) shows how to use it together with WPF Binding.
Related
In many ways I think of using the MVC pattern in WinForms, but I'd like to know if it's possible to bind controls with objects using the ObservableCollection type? If it's purely for WPF, what other alternatives are out there?
To put it into perspective, we're building a system which has business logic that I'd like to control the UI with, instead of making customizations for each requirement or workflow on the UI itself. We have around a few hundred potential forms which I'd like to start designing with the pattern in mind.
We're also building web interfaces for most of the processes, but in reality they're just watered-down versions of the Forms. If I can use the same framework which I can just bind to on the web form that would be awesome.
Thanks
What ObservableCollection does is that it implements INotifyPropertyChange and each control in WPF has the possibility to listen for it's bound data to raise the event from INotifyPropertyChange. You can read more here about why you can't use ObservableCollection they way you want to in WinForms.
Another way is to use the Model-View-Presenter pattern:
This pattern can also be used in ASP.NET.
There's an MSDN Magazine Article on: "Better Web Forms with the MVP Pattern" that I think you should look into. And here is an introduction to how you use MVP-pattern in asp.net.
In MVC a model can have multiple views, in WPF a XAML code-behind model is tight to 1 single XAML (view) isn't WPF/XAML flawed from the start in respect to MVC ?
I recommend looking at MVVM for use with WPF.
You're comparing MVC with Windows Forms to WPF with code behind - which is comparing an architectural pattern to a technology (without using a pattern). This is an unfair comparison.
I wrote a series on MVVM starting from a Windows Forms perspective that may help with understanding this. You'll find that the separation of View and ViewModel possible with WPF is far cleaner and simpler to implement than the Controller of MVC. It actually allows even more decoupled architectures with less implementation work.
Good question!
In MVC you state that a model can have multiple views, which is true. However, each view would have its own controller.
In MVVM a model can have multiple views, and in this case each may have their own view model.
However, in practical terms, if a ViewModel does not have any concepts that are highly specific to a certain view, it is entirely possible to re-use view models. In fact, I wrote an article on cross-platform XAML applications where I re-used code between three apps, one on WP7, one in Silverlight, the other WPF:
http://blogs.msdn.com/b/mikeormond/archive/2010/12/09/writing-cross-platform-xaml-applications.aspx
The views for each were very different, however I was able to re-use both the models AND the view models for all three apps.
WPF/XAML is a technology, and MVC is design pattern, it's good when technology is not limiting you to a specific pattern, and allows developer to choose what pattern to use. Same as programing languages allow's you to use any design pattern.
You can use MVC, MVP, MVVM, or YourMegaPattern with XAML\WPF. Technology should be above patterns, it's frameworks that are usually bound to a specific pattern.
For example you can take ASP .NET techology, and MVC framework based on it.
How to use MVVM in WPF Browser Application?
I want to know how to use MVVM in WPF Browser application,
Is that really worthful when comapre with Silverlight?
Which technology is having higher performance for mvvm Silverlight or WPF?
I am going to have my Business layer using ASMX 2.0 (or) WCF
Please help me on this,
Thanks in advance.
A good place to start is by looking at the PRISM framework. It will allow you to implement the MVVM pattern in a WPF browser application. I have been using this technique for sometime without any issue.
I'm a newbie to WPF and I'm developing a brand new windows desktop application and I would like your opinion on what WPF framework I should use. I know this question has been asked before, but the last question was asked at least several months ago. A lot has changed since then.
Right now, I'm using MVVM Light which is more of a library than an actual framework, as the name suggests. I’m looking for something more comprehensive. I prefer a framework that I can use on future WPF projects. Consequently, it should be general purpose and productive.
Any insights or suggestions?
If you are a newby I would suggest that you try to use PLAIN WPF first to get a feeling for it instead of right away extending WPF with other frameworks.
Your title is a bit confusing. WPF is just a graphics/UI layer. WVVM is a Model View ViewModel framework, for implementing a MVVM pattern using WPF ( or Silverlight ).
So, are you asking what design pattern you should use for your WPF application? ( As in MVC, MVVW, MVP, etc... ) Or are you asking which MVVM frameworks are compatible with WPF?
Ugh, acronym soup.
As to my answer, if you are new to WPF and want to learn WPF, I would start with no framework, you can always refactor later once you have a good solid grasp of the underlying technology.
It's definitely on the heavy weight end, and plenty of people will warn you about it, but you seem to be asking for CAG
http://compositewpf.codeplex.com/
It's a pattern that comes with a sample implementation that you can bend into your own. For example, it comes with Unity for IoC, but you should be able to put in another IoC container.
The download comes with a lot of samples for both Silverlight and WPF.
Caliburn (http://caliburn.codeplex.com/) handles a lot of shortcomings of the WPF inherent model (like writing a ton ot stupid routing code for events) and introduces MVVM ;) My bet ;)
You might have a look at the WPF Application Framework (WAF). The sample applications show:
View composition
UI Workflow (Wizards)
Command binding / Shortcut Keys
MVVM pattern, Unit Testing
Validation
Entity Framework
Open/Save FileDialog
Print Preview / Print Dialog
Localization
Are there any MVC frameworks available for WPF other than Caliburn (which looks awesome btw)?
Both Caliburn and PRISM are very nice. However if you go down the path of MVC you will miss out on the powerful 2 way binding. Consider MVVM, it's a very clean and practical approach for WPF. This is the pattern Microsoft used for their expression blend.
There is also Magellan, a port of ASP.NET MVC for WPF.
There is Composite WPF aka PRISM from Microsoft Pattern & Practices.
http://www.codeplex.com/CompositeWPF
one additional possibility is pureMVC (www.puremvc.org)
it seems well-proven, has good short doc/UML, and the project is responsive, and has been ported to .NET - there exists an WPF demo, it will be published soon but you also can contact the project owner about it.
Regards,
Paul
A new MVC framework that works with practically and .net technology (WebForms, WinForms, WPF, Xamarin Forms) is SimpleMVC by Gateway Programming School. This link gives an overview and example usage.
A short example is to create a controller from SimpleControllerBase that has your business logic. This will depend on the SimpleModelBase implementations you provide. Implementations of ISimpleView are handled through WPF pages and controls. The derived controller only works with the interfaces that extend ISimpleView so that the WPF parts are abstracted away. You then use properties on the view to do two-way data-binding, just like MVVM, but with a proper layered architecture.