Just out of curiosity, wanted to know if there is a need to use any MVVM frame work available as third party installable or we can directly create and define different projects in our application and call them as Model, ViewModel and View, and also use them as per their definition.
Does the third party framework provide anything extra and can a application as mentioned in the above paragraph can be called as MVVM compliant.
No you don't have to use any third party framework, you can just follow the design pattern. You can follow this link to find out more.
http://www.silverlight.net/learn/advanced-techniques/the-mvvm-pattern/using-the-mvvm-pattern-in-silverlight-applications
If you're looking for an MVVM framework then I would suggest Catel
The approach which you're thinking of is not what I personally would call 'MVVM compliant' (altough it is only a pattern). Normally your Models are classes to describe and access your data (Linq2Sql entities), ViewModel are classes which drive the applications business logic and your Views are just windows/pages etc.
Normally I just create folders in my main project for all three of them and take it from there but sometimes it is a good idea to get the Models into a separate project if they are going to be used by other ones but I would normally call it something like MyProjectData
No, it's not necessary to use any of the available MVVM frameworks, you can create your own MVVM framework and use it. If you folllow the guidelines for MVVM patern and implement the framework correctly then the application would be MVVM compliant.
But yes MVVM frameworks have there advantages, they provide a lot of features/base classes out of the box which you will have to implement yourself in your custom MVVM implementation; for e.g. Prism provides a standard way of solving various problems/scenarios encountered in SL or WPF application (EventAggregator, Navigation framework, commanding etc.).
Have a look at this question which I had asked about Prism -
Custom MVVM implementation Vs. PRISM
No, you don't need to use third party framework for it. You just need to follow the architecture of MVVM and try to implement your code in that. Your can learn more about MVVM here enter link description here
Best for MVVM Architecture
Related
I'm currently searching what will be the Framework that we will use for our nexts applications. Currently we have applications running with winform and we plan to switch slowly to WPF(with new application, and then refactoring the GUI). We are a team of 9 people working this solution.
We have a big solution(currently, 300+ VS projects, ~1'500'000 line of code), so when choosing a framework, we are looking for something which will promote a clean code, a good infrastructure, but also a framework that will not slow(too much) the application.
Currently, I'm mainly interessted in Prism(which seems to be a little bit complex to fully understand) and Caliburn.Micro.
The Caliburn.Micro seems easier to use, but I'm a little worried that all those convention oriented stuff means that a lot of things will be done using Reflection on runtime.
Am I correct? Or is this something done at the compilation ?
Also I'm not sure I should consider MVVM Light, since it lacks of documentation/targeted application sizes.
First of all, Prism is not a MVVM framework. There is Prism.MVVM and it is a very lightweight MVVM library and it's independent of Prism.
Second, this <ListBox x:Name="Products" /> automatically databound to viewmodel should not be a performance problem in Caliburn.Micro, because plain Binding in WPF uses refelection anyway. Not sure if Caliburn uses reflection internally as well, but even if it does, it's hardly noticable at runtime if you dont do it in iterative scenario, e.g. inside ItemsScontrol with 1000+ items. If you experience preformance issues, nothing prevents you from writing it the standard way. However, the added value of this is questionable. IMO it brings more problems than it solves
If I may give you my advice, don't use any MVVM framework. All you need is INotifyPropertyChanged implementation and DelegateCommand (ICommand implementation). In some special cases you may need EventAggregator. Now tell me, are those three classes worth a framework? No, the aren't. Why introduce a dependency to a third party library?
If you are going to start such a large solution, the investment to write your own base class library is negligible. You can always take the source code of a class or two from Prism and use them in your own library.
The problem with those framework is that developers tend to over-engineer simple scenarios, such as using EventAggregator where plain event or even direct reference is more suitable. Or take Prism as an example, they use regions and view injection where simple ItemsControl could be used.
After 6 years experience with WPF I became a big proponent of ViewModel-First approach. MVVM then becomes much simpler. But most frameworks work better with View-First approach.
So, my vote is to not use any MVVM framework. If you have to use one, choose Prism.MVVM. And look at the source codes, they are well written.
I have used CM for a few years, start back when it was 1.1. I came over from PRISM. While I agree for some of the comments and points of view from other posters, you truly only option at this stage is to get the library/framework (which ever you choose to play with), wire it up and run with it a little bit in your off time from major projects. Implementing it on your "paid time" might be less than beneficial since you will undoubtedly have questions while "experimenting".
Experiment first then make your decision. Want separation of concerns? Want rapid development? Want to be able to drop a control on workspace name it and it will just work (assuming it has a built-in convention, or create your own convention for a 3rd party control), wire some viewmodel code up to a property or method that you named the control, then give Caliburn.Micro a try. Don't want to use Caliburn's conventions then don't. Just about everything for CM is modularized in to core needs with Nuget installs.
There are many MVVM frameworks as well as libraries all have different niche areas some are multi-platform, some are laser targeted on 1 platform. You can only use what you try and at the end of the day if you find something you like using and it works for you and your team, then it (framework/library) is the one that should be targeted.
Example of why I left PRISM
On the View
<Button x:Name="ClickMe" />
In the ViewModel
public void ClickMe()
{
}
public string FirstName
{
get{...}
set
{
_firstname = value;
NotifyOfPropertyChange();
NotifyOfPropertyChange( () => CanClickMe); )
}
public bool CanClickMe
{
get { return !string.IsEmptyOrNull(_firstname); }
}
Most WPF performance problems are not caused by the MVVM framework but how you implement your WPF application (e.g. are you using virtualized lists?). I think you should select your MVVM framework depending on your function needs (are all functionalities available, e.g. a command implementation, view model base class).
It is more important to define conventions and rules for implementing your MVVM/WPF and select the MVVM framework based on these rules. Some conventions and rules can be found in my article about recommendations and best practices for implementing MVVM and XAML/.NET applications.
There are lots of resources about choosing the right MVVM framework, for example:
What framework for MVVM should I use?
https://social.msdn.microsoft.com/Forums/vstudio/en-US/c8accd7e-69c1-48af-bf5a-4275910c2b9e/which-mvvm-framework-to-choose
I've been learning SL over the past month and have now shifted my focus toward UI Pattern Frameworks such as Caliburn.Micro and MVVM-Light.
I recently attended a session at a conference on Using the MVVM Pattern with WPF and SL. The presenter demonstrated using the pattern plain, without any UI Frameworks -- very simple and straight forward. In the presentation he recommended that we create a base VM to be able to use some common functionality (wasn't able to get more specifics due to time -- please feel free to clarify). Is this a reason why I would want to use a UI Pattern Framework?
My understanding is that UI Pattern Frameworks help implement patterns like MVVM by convention, thus allowing devs to not have to worry about that. Why else would I use a UI Pattern Framework?
Thanks in advance!
Rich,
For business app - your VM most likely going to need at least 2 interfaces:
INotifyPropertyChanged and INotifyDataErrorInfo
Like Kieren said - implementing INotifyPropertyChanged is very easy, couple lines of code. INotifyDataErrorInfo is little more but not bad.
MVVM Light is so "light" I'm not even sure what's is the point :) To me - someone who understands what MVVM about doesn't need this. You can look at it's source code to see what it does because most likely you will need to expand on that base class.
Caliburn, OTOH, is a convention-based framework which allows you bind without specifying "Bindings" and other magic like this. You need to decide if you really need it...
If you are working on something heavy, like LOB application with lot's of forms and stuff - I strongly suggest looking into PRISM. It's not an MVVM framework, it's framework to build complex composite UI. Learning curve will be steep, not like MVVMLight :) But it will cover most bases in your business application.
The only reason to use a UI Pattern Framework is if it provides the functionality you need or want.
If you only need to use INotifyPropertyChanged and maybe a quick RelayCommand, write them yourself (since it's ~5 lines of code, a couple of classes, ~30 lines in all).
If you need more, use one of the pre-built frameworks.
I am working on Silverlight 3.0 and currently using code-behind in my Views. I would like to implement the MV(VM) pattern into my project as the project is growing. I have seen some WPF projects where the code-behind has NO CODE except for the InitializeComponent method, which I believe is the right way to go and just looks clean. Is this possible in Silverlight 3.0, that is, no code-behind?
Can anyone point me to some good Silverlight (3.0) MV(VM) tutorials / articles?
Without using some additional framework, Silverlight 3 does not support what you saw in WPF. Specifically, full Commanding support. Silverlight 4 has included Commanding for Buttons, which is a start.
You can look into other frameworks that provides this feature set, like Prism. This will get you along the right path, but I'm sure there are other options.
You can follow the MVVM pattern for Silverlight 3 applications without using a framework. However, it is much easier to use one of the many MVVM frameworks out there. Here are a few good ones:
MVVM Light
MEF
Simple MVVM
I'd recommend not using Prism as it is more complicated than it needs to be.
Other options include things like MVVM Light, which is lighter weight alternative to Prism for things like handling events and commands, however Prism does have a lot of functionality (and the Prism 4 talk has that sounding like a good option when it gets released).
One good community site to check out is the Composite Development Patterns Community, which was newly started but has an excellent goal of collecting articles and other help for working with development patterns like MVVM.
Lastly, John Papa gives a great overview of MVVM, limited to links so head to Google and look up "John Papa MVVM". :)
One thing to consider though, resources for SL3 aren't going to be as valuable as those for SL4, which opens up additional options for framework based commanding (ICommand that greglev mentioned), although it isn't still the full command support from WPF.
Jesse Liberty has a good primer on MVVM also using Behaviors for wiring events.
Silverlight and MV(VM) Pattern - No Code-Behind - Is this possible?
MVVM is most commonly used with WPF because it is perfectly suited for it. But what about Windows Forms? Is there an established and commonly used approach / design pattern like this for Windows Forms too? One that works explicitly well with Windows Forms? Is there a book or an article that describes this well? Maybe MVP or MVC based?
I have tried MVP and it seems to work great with windows forms too.
This book has an example of windows forms with MVP pattern (sample payroll application). The application is not that complex but will give you an idea about how to go about creating it.
Agile Principles, Patterns, and Practices in C#...
You can get the source code at
Source Code
EDIT:
There are two variations of the MVP pattern
(a) Passive view and (b) supervising controller
For complex databinding scenarios I prefer to go with the Supervising controller pattern.
In supervising controller pattern the databinding responsibility rest with the view. So,for treeview/datagrid this should be in the respective views, only view agnostic logic should moved on to the presenter.
I'll recommend having a look at the following MVP framework
MVC# - An MVP framework
Don't go by the name (it's an MVP framework).
Simple winforms MVP video
Winforms - MVP
An example of dealing with dropdown list
MVP - DropDownList
Simple treeview binding example (poor man's binding). You can add any treeview specific logic in BindTree().
Below is the code snippet.... not tested, directly keyed in from thought....
public interface IYourView
{
void BindTree(Model model);
}
public class YourView : System.Windows.Forms, IYourView
{
private Presenter presenter;
public YourView()
{
presenter = new YourPresenter(this);
}
public override OnLoad()
{
presenter.OnLoad();
}
public void BindTree(Model model)
{
// Binding logic goes here....
}
}
public class YourPresenter
{
private IYourView view;
public YourPresenter(IYourView view)
{
this.view = view;
}
public void OnLoad()
{
// Get data from service.... or whatever soruce
Model model = service.GetData(...);
view.BindTree(model);
}
}
As it has already said, i always worked in a MVP pattern when using Winforms. But the design pattern you will use not mean you will use right. There is loads of anti-pattern attached to MVP.
If you want to starts everything in a good manner, you have to use the framework for building smart client. So i will recommend to use that design and practices: Smart Client Software Factory http://www.codeplex.com/smartclient
You have a discussion here about the current smart client frameworks : http://codebetter.com/blogs/glenn.block/archive/2008/05/10/prism-cab-and-winforms-futures.aspx
PS: I like this post on the MVP anti-patterns: http://blog.mattwynne.net/2007/06/13/mvp-smells/
Hope this helps
The Model-View-ViewModel (MVVM) Pattern is a design pattern. Per definition a design pattern shows a common solution in the object-oriented world and this solution can be applied in various platforms (WPF, WinForms, Java Swing, etc.). I agree that MVVM is best used with WPF because it leverages the strong binding capabilities. However, Windows Forms supports data binding as well.
The WAF Windows Forms Adapter shows how to apply the MVVM Pattern in a Windows Forms application.
I have written about a variation of MVP/MVVM design patterns called MVP-VM, which is a tailor made solution for winforms applications that require full testing coverage and use data binding as main mechanism for keeping the presentation updated with model data.
MVVM for .NET Winforms
MVVM (Model View View Model)
introduces similar approach for
separating the presentation from the
data in an environment that empowers
data binding (WPF). Since .NET
framework 2.0 already offers advanced
data binding infrastructure that also
allows design time binding of
application objects - the ‘View Model’
entity can fit quite well in MVP based
environment.
I asked this same question to two of my techies co-workers: is MVVM for WindowsForms possible? Both gave me the exact same answer: "No way! WindowsForms is missing the rich bindings of WPF and Silverlight (OneTime, OneWay, TwoWay, OnewayToSource) and it is also missing the TypeConverters."
Screen Activator Pattern for WindowsForms - you can find it here, ported from Caliburn.Micro by jagui
Rich Bindings and TypeConverters - Truss by Kent Boogaart, does it in an UI independent way
Commands - WPF Application Framework (WAF) has a WafWinFormsAdapter project that takes care of some MVVM stuff namely commands
Again, can we have MVVM for WinForms?
Yes we can. We have all the pieces. We just have to glue them together.
I believe that MVP is a pattern well-suited to WinForms development - as is partly evidenced by it's use in CAB - Microsoft's framework for WinForms.
I use MVP in WinForms to extract code out of the View - because I can't test the View code. And also to enable code that needs to be reused (or is duplicated) to stay out of the View where it can't be shared.
I can refer to my own project where I use the MVP pattern ExceptionReporter.NET. Though I'm sure I don't use it perfectly.
You mentioned MVVM working for WPF - I think the reason for that is because of strong data-binding support. If you were not using data-binding in WPF (and it's certainly not compulsory) then you could choose MVP. The point being that MVP is a strong choice for any client-side application. And possibly a 'better' choice, even in WPF, if you plan on sharing code between projects that aren't WPF.
For more evidence of the value of using MVP in WinForms see Boodhoo's video presentation on using MVP:
http://www.bestechvideos.com/2008/06/29/dnrtv-show-14-jean-paul-boodhoo-on-model-view-presenter
And an MSDN article by the same author at http://msdn.microsoft.com/en-us/magazine/cc188690.aspx
The BindTree method seems a little
flawed to me. Suddenly the the View
knows abou the Model. Is that a good
thing? There must be tons of poeple
being confronted with these kind of
problems. I am surprised that there
aren't any books about it. Since there
are books about everything in the .NET
world.
These Design not about hiding the model rather precisely defining the interactions between the different layers of the applications. You can change the backend completely and as long as you pass a Model through Bindtree your UI will continue to work.
Now class Model may be a poor choice of a name in the example that Rajesh gives. It can be TreeData, or RecordsData. However you define it, it has what you need to using the binding mechanism of Winforms to bind a specific control to the underlying data.
The best site to browse for this kind of material is here. Martin Fowler has collected a variety of useful UI design pattern and enterprise design patterns.
Again the key to this is the use of interfaces to precisely define how each layer interact with each other.
In my own application (a CAD/CAM applications used to run metal cutting machines) my structure looks like this.
Forms implementing form interfaces
UIDLL with views implementing view
interfaces that interact with forms
through the form interface. The
specific views register themselves
with UIViewDLL Views executes Command Objects found
in command libraries that interact
with the Model.
Command libraries; lists of
commands implementing ICommand.
The command that interact with
views do so through the interfaces
exposed in UIViewDLL.
UIViewDLL; exposes the View Interfaces
used by the commands.
Model; the classes and collection that
make up core data structures of my
application. For me these are things
like material, cuttingpaths, shape,
sheets, torches, etc.
Utility; a DLL that has commonly used
utility classes used by my company
that span different application. For
example complex math functions.
You can use Enterprise Architecture, Patterns and Practices as the starting point, although they are slightly dated.
Under General Guidance there is Application Architecture for .NET: Designing Applications and Services, which is a good introduction to .NET ways and layered N-tier application.
alt text http://i.msdn.microsoft.com/ms954595.f00aa01%28en-us%2CMSDN.10%29.gif
For more formal "patterns", there is Enterprise Solution Patterns Using Microsoft .NET.
(source: microsoft.com)
To name a few,
Model-View-Controller
Intercepting Filter
Three-Layered Services Application
The first good explanation of UI design patterns I read was in Jeremy Miller's blog - Building Your Own CAB. It describes the common patterns - Passive View, MVP, etc. and addresses some of the ways you might implement them in C#.
You can try MugenMvvmToolkit that allows to use a "pure MVVM" for WinForms.
Due to the fact that it supports bindings on all platforms, all of the native binding features available for WPF platform available on all platforms (include WinForms).
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.