Some body can share with me some example that use MVVM Light, where one view exists in each project (the solution has multiple projects, one for each view). What happen with the Locator, need to have one for each view in each project? How sincronize the view? How animate the initializacion of each view?.
Thanks a lot
Why does each project only have one view? That seems inefficient, unless you're dynamically loading the XAPs of the other projects at run time. If that's the case, there would still be one main Silverlight project as a starting point, and that's where the ViewModelLocator should be.
I would need more information about the structure of the project and the business goals before being able to provide more details.
Related
I'm trying to figure out what would be best solution to the problem I'm facing. I have a Silverlight application which should be composed from different modules. I can use Prism, place regions and load modules and fill regions with loaded modules but this is not enough in my situation. Here's what I want to accomplish:
For most views that gets loaded from different xap files, I should place an element somewhere in the shell, which will perform navigation to the dynamically loaded view.
That element (which links to dynamically loaded view) should support localization and should have dynamically assignable data templates, different module links should have different content/data template (I'm thinking writing data templates in xaml files on the server and reading them from silverlight via XamlReader, maybe there's a better way?).
Uri mapping and browser journal should work with navigation. Silverlight default navigation mechanism better suits my needs than the one found in Prism.
The architecture should support MVVM.
I think thats all. I just couldn't think of a good architecture which will satisfy all my needs. Any help would be greatly appreciated.
I do not know of a single product/solution that would cover all your requirements, so here are some comments on each:
If one area of the shell has a region that supports multiple items, you just register a control of type link/button etc with the same region name in each module. For example we register views based on the Telerik TadRibbonTab (instead of UserControl) with a region named "views" which is a RibbonBarTab with a region named "views". Every module then adds its its own button to the list. You can do the same thing with any multi-item container.
Localisation is a completely different issue and can be solved in a number of ways. See my answer here: Load Resources ".resx" from folder in Silverlight
A custom navigation mapper can be made to behave like the standard one, without messing up the support for Prism regions. The one we created encodes GUI information such as current selections (current view and item selections etc) into the URL. That means we are in total control of the state and the URL controls the state.
Hardly anything stops you using MVVM as that is one small feature for separating views from code-behind data.
I will be interested in what other solutions are proposed as we are always looking for new ideas too.
The MVVM approach encourages (or just gives the possibility to) splitting a WPF or Silverlight application into Model, ViewModel and View projects so all three could exist in their own assemblies.
Using Prism (and, in my case, MEF as a Dependency Injection Container), on the other hand, one can build a modular application that is divided into a set of functional units (named modules) and each unit, in this case, is a seperate assembly.
Am I right that in this case we can separate only a Model in an its own assembly, but View and ViewModel should sit in one assembly, representing one functional module?
First of all, module is not equal assembly. You can spread a module's parts between several assemblies (including Models, Views and ViewModels). Although, usually you place classes related to a module together in one DLL or XAP file (in case of Silverlight if your module is a separated Silverlight application).
As of your case, if a Model is a shared entity which can be used by several modules, Prism encourages to place it in so called Infrastructure assembly that keeps shared non-module specific logic. Otherwise, it could be a good idea to place MVVM parts together, since they solve common business tasks. In the future, if you need to replace implementation of one of the MVVM's parts, you can do it just adding a new one and adjusting container's mapping.
Yes, Prism encourages you to put everything (models, views and view models) into one self-contained functional module.
In any case, I would strongly NOT recommend you splitting views and view models into separate projects. This is because they are tightly coupled together and are developed side-by-side.
Well, there are two recommended approaches on how you organize you MVVM application. First is when you organize your project by layers and put you views and view models into separate folders inside a project. Second, when you create folders by feature and don't separate views and view models, i.e. they lie in the same folder side-by-side. I personally choose the second one because, as I mentioned, they are developed and maintained always together and this way it is very easy to find corresponding view or view model.
I am new to Silverlight/Prism, so not sure how a new layout page would be rendered. I've got the Shell working like a master page, but I want to have several pages in the application with a different layout master. So, how do I get another (shell) or layout page to arrange different regions?
Thanks for any conceptual feedback!
Have you considered having your Shell view contain either a ContentControl or a ItemsControl so that you can programmatically load different views. These different views could then contain regions or whatever you wanted.
I'd also remember that PRISM is likened to a buffet, you can pick and choose which parts to use. Once you look at ItemsControl and ContentControl consider what regions offer.
Treating Prism regions like Master pages seems to always lead to confusion. It is not designed (like ASP.Net) to potentially render a new shell around every page that appears. That was created for a Browser -> Server -> Browser model where the page is recreated on every request.
To implement a master page style scenario all you are really doing is providing a choice of outer shells that have the same region names defined, but in different visuals or positions. Changing the shell via an element/region in the root visual will cause all the child regions to repopulate in their new homes.
Personally I treat Silverlight more like I would a desktop application and less like a website. I dropped the idea of Master pages (as it feels backwards) and just use dynamic styling for overall changes.
Hope this helps.
The following thread deals with a similar situation. I hope it is useful.
http://compositewpf.codeplex.com/Thread/View.aspx?ThreadId=671911.
Thanks,
Damian.
I have an app that has several modules that have completely different functionality and I'm trying to figure out the best way to implement this using prism.
To try and better explain, I'll try to use Northwind as an example. I have 3 modules, orders, customers & employees.
The customer module will allow you to do anything pertaining to a customer. Add, remove and edit. I'm going to use scope regions for the main view in the customer module to handle all the different views I need to show here.
In the scenario above, I only want to load a module when a user wants to work with say a customer, order or employee.
You have these modules laid out and realize that you need to be able to show Orders for customer or sales people which are obviously employees.
What would you do here in this scenario as you wouldn't want to create an entirely new modules for say employeeOrders and customerOrders and you wouldn't want to duplicate any order related code.
I'm starting to wonder if it's feasible to think about building a composite application using prism if you're building an app like Outlook, but for a LOB business app, I've yet to find a good sample of how to do this and not break some of the principles of MVVM and definitions of Prism in order to do so.
I'm just 3 weeks into Prism and still learning but this is the biggest issue I'm running into.
Any thoughts?
You should be using the Event Aggregator for these types of communication scenarios. Essentially, you want a module to provide functionality but also expose events that can be invoked from other modules. You can also register a service in the Unity container. For example:
public interface ICustomerOrderInvoker
{
void DisplayCustomerOrdersInRegion(string customerId, string regionName);
}
These techniques are somewhat orthogonal to MVVM. Your event handler can create a view/viewmodel pair and insert them into a region. Or your event handler can create a UserControl with all functionality implemented in code behind and adds it to a region. The beauty of the composite UI is that your modules can use MVVM and another team's modules can use straight forward user controls or MVP or MVC or anything really; the point is that all the modules are composed into one application regardless of how they are implemented because they use the patterns established in Prism like regions, events, etc.
In your particular case:
You have these modules laid out and realize that you need to be able to show Orders for customer or sales people which are obviously employees.
Your Order module will certainly be aware of the concept of a customer id since the Order entity is associated with a customer. The Order module should expose an CompositePresentationEvent that displays a view that has all the orders for a particular customer id.
The point of Prism is to create logically separate and loosely coupled pieces of functionality. This does not mean that the modules do not communicate with each other, but rather that the communication happens in a limited and loosely coupled manner. You can certainly write LOB applications using this pattern and MVVM; many of us have been for years now. :)
Im working on a similar problem (and am new to Prism too), as yet don't have a solution. I think when using Prism its tempting to use the framework as the reference implementation intends, but it doesn't need to be so.
Prism should (when used correctly) facilitate software development, not hinder it. So don't get too stuck in the idea that any implementation must meet strict decoupled refactorised super patternised standards!
What I am doing/intending to do is create a MainModule, which has in it much of my core functionality, including a MainView/MainViewModel user control. The Shell then has one region "Main" and on MainModule load the MainView is injected into it as per standard prism usage.
I'm using a Docking Manager from Telerik (compatible with Silverlight and WPF) on the MainView and have implemented a class IDockingManager / DockingManager class in Infrastructure which is registered with Unity as a singleton (ContainerControlledLifetimeManager) in the bootstrapper.
Anywhere in my app I can get the IDockingManager instance and inject a view by calling IDockingManager.DockView(IView view, DockingParameters args). The DockingParameters can contain information such as where to dock (Left, right, top, bottom, tabbed document) and also the parent container to dock in.
This is the part I've not got to yet - I can dock left/right/top/bottom on the main view but I want to implement an attached property or something on my child views registering them as a DockSite when docked. So for instance I could dock a Treeview on the left and dock underneath that a listview by using the Treeview name as parent DockSite and DockBottom as the side.
Hope that makes sense, I've rambled without really explaining too well. Basically what Im saying is Im not using regions at all (except to inject the MainView) in this application and have created a class to handle view injection into dockable containers. It's not strictly Prism but Prism is there to make my life easier, not the other way around ;)
I am developing a WPF application using the CAG from Prism. What I want to achieve is create new instances of a module (ModuleA) and load them in a TabControl.
I am able to instantiate the modules using the moduleInfo object and loading them through the Assembly and calling the CreateModule(type) method.
I can actually see the different modules in the UI, but the problem is when I start interacting with the different modules (for e.g. loading or unloading views in scoped regions) all the activity seems to happen only on the last loaded modules.
So for e.g. I have 2 'instances' of ModuleA as 2 TabItems and they both have command buttons to Load() new views. When I select the first Module (by selecting the first TabItem) and click the button to laod the view, the view gets loaded in the second module.
Anyone know how to sort this problem? Makes me believe, even if I 'see' two seperate modules on the UI, there is actually only one instance or the CreateModule creates clones ?
Anyone ? all help appreciated !
As Erik explained, loading Modules and Views are very different concepts in Prism.
The following threads are useful when understanding this and deal with a scenario similar to the one from the question:
http://compositewpf.codeplex.com/Thread/View.aspx?ThreadId=59827
http://compositewpf.codeplex.com/Thread/View.aspx?ThreadId=59040
I hope this is useful.
Thanks,
Damian