I am considering building a application using PRISM (Composite WPF Guidance/Library). The application modules will be vertically partitioned (i.e. Customers, Suppliers, Sales Orders, etc). This is still all relatively easy... I also have a Shell with a main region were all the work will happen but now I need the following behavior: I need a menu on my main Shell and when each one of the options gets clicked (like customers, suppliers, etc) I need to find the module and load it into the region (Only 1 view at a time)?
Does anybody know of any sample applications with this type of behavior? All the samples are more focused on having all the modules loaded on the main shell? And should my menu bar also be a module?
[UPDATE] How do I inject a module into a region based on it being selected from a menu? All the examples show that the module injects the view into the region on initialize? I need to only inject the view if the module is selected on a menu?
Yes PRISM will help you out here.
A number of things here worth mentioning.
RE: Is Prism right for me?
You can load a Module on Demand. PRISM has the capabilities of loading a module at RunTime, so in your case if you bootup the said solution using Shell and ModuleA. Your user then triggers an event (ie Menu choice) it can then allow you to dynamically load ModuleB and then inject that into play. To be clear though, you really need to sit down and do your homework here as you need to ensure ModuleB doesn't have any of its own dependencies on other modules etc (typically its wise to use an Infrastructure Module. I've used techniques where i have a manifest of modules that i lookup in XML that lists its absolute dependencies and then I make sure they are loaded first, then I load ModuleB).
See Load Modules on Demand via PRISM help docs (Development Activities). Also lookup Prepare a Module for Remote Downloading
RE: Injecting a view at runtime
To inject a View into a Region via Menu is a simple case of accessing the IRegionManager and then adding it. To do this, make sure in your Constructor for the said ViewModel/Presenter/Controller you're using put:
MyConstructor(IRegionManager regionManager, IUnityContainer container)
As with PRISM you can pretty much add any object you want into your construct and PRISM will ensure it arrives there on time and on budget (hehe).
From there its the normal approach you'd take with adding a view... eg:
IMyViewInstance myViewInstance = this.container.Resolve<IMyViewInstance>();
IRegion myRegion = this.regionManager.Regions["YourRegion"];
myRegion.add(myViewInstance);
myRegion.Active(myViewInstance);
And all should come together! :)
Note:
Make sure you set a local reference to the container and regionManager at Construct (this.container = container etc).
If you're not sure where the above namespaces exist, right click on IUnityContainer for example and let Visual Studio RESOLVE it (right click menu)
Put the Add logic into your Menu Event that or use a central method - whichever blows your hair back :)
Scott Barnes - Rich Platforms Product Manager - Microsoft.
Just finished watching Brian Noyes on Prism at dnrTV. This answered all my question...
It's not clear what you mean saying "find the module and load it into the region". You can load module's view and add it to shell. Composite UI app block and CompositeWPF are built on top of the IoC pattern. It means that your modules should inject their menu items in shell's menu strip or subscribe to events generated by shell.
You could have your main region be a ContentControl, this way only 1 view will be active at a time.
You can also load your modules "On Demand". There is a Quickstart that shows you how to do this. You should also keep in mind that if the module was already initialized once, initializing it for a second time will not execute the Initialize() method on the module.
It might be useful that when you click on the menu, this will load the module on demand (which will not load the view yet) and then you can fire an event through EventAggregator, so the module can now add the view (use the named approach for not adding the view twrice) and the Activate the view (which will make sure the view is shwon in the region).
Hope this helps,
Julian
to save you time, check John Papa's Presentation Framework article. It will be more easy if you have 3rd object(Screen Conductor) to handle your screens in showing or hiding from regions.
Related
I've been creating a WPF application that initially loads as a task bar icon and then when clicked opens an appropriate window. This was a prototype and I want to move over to Prism and having watched the (superb) videos by Mike Taulty (channel9.msdn.com/niners/mtaulty) I have the feeling that what I need to do is create an application with a custom bootstrapper that does all the service registration but does not create an initial shell but instead simply loads the modules and perhaps identifies a module to Run. Has anyone anyone done something similar, if so how much work am I in for?
OK I bit the bullet and just tried it. I should first state that I was using the Autofac version of the Bootstrapper.
I returned null to CreateShell
I marked the apps ShutdownMode="OnExplicitShutdown" in the declaration at the top of App.Xaml (important otherwise it closes the application when you close the last window)
I created a module (IModule derived) that loaded the WPF notify icon by Philipp Summi (http://www.codeproject.com/Articles/36468/WPF-NotifyIcon)
In response to a command from the context menu on this icon I simply create the window and it's view model and show it.
This all works just as I had hoped. The only thing I have yet to do is see how to use regions with these temporary windows although other articles appear to have this covered. I'm not convinced the Autofac bootstrapper gives me any great advantages but I had developed a very early prototype using Autofac and stuck with it because it went smoothly. I will probably go with Unity or MEF in the long run just to avoid compatibility problems and to allow dynamic module loading from external plugins.
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.
I will be starting a new project soon and am looking for some architectural advice from those of you who have experience with WPF, Prism, and MVVM.
The project will definitely be WPF and I will be implementing MVVM (I will likely use Josh Smith's MVVM Foundation as a starting point) in order to be able to benefit from the separation of UI/logic etc. I am not sure though if I would benefit from using Prism as well to structure my project.
Let me briefly describe the project. There will be a main "toolbar" that will display a number of widgets. Each widget displays some basic data related to its function and clicking the widget will open a new window that will display much more detailed data and contain a rich UI for viewing/editing the data.
Now, I was thinking that I can use Prism to frame the project but I have never used it before and am not sure if it is suitable for what I am trying to achieve. For example, would my "toolbar" be a shell that contains regions that each widget would populate? Would each new window that is displayed when a widget is clicked also be its own shell with its own region setup? If I can get the pattern down for the toolbar and one widget on the toolbar, I can replicate it for the rest of the widgets.
Aside from Prism, I have a question about how MVVM should be implemented for certain data editing windows. Let's say I have a chart that displays some data and the user is able to directly click/mouse move on the chart to edit the data that he sees. All of the data is in the model and the view model is making that data available to the view via binding. My question is where will the mouse click/move events, that are specific to the chart in that view, be written? We don't want much/anything in the view's code behind and we don't want to have UI event handlers in the view model so I am not sure how this type of scenario is handled. I know that commands are the likely answer here but the MVVM samples I have seen usually show sample commands for simple button clicks. Is the general idea the same?
So, if anyone has any suggestions on the above or any general tips on working with WPF and MVVM/Prism, please let me know.
Thank you.
There are a few questions in there so I will do my best at covering them all.
I worked on a project that had WPF, MVVM, and Prism along side other frameworks. The best advice is to understand the power and functionality of each before glueing it all together. You don't have to use all the features of Prism for it to be useful in this situation.
For Prism you can use...
Shell and bootstrapper to initialise the application and load modules from other assemblies.
Create and configure Unity for Dependency Injection. You can use other DI Containers. Here you can add global services each module will use.
Use of EventAggregator to notify differnent parts of the application, usually across modules and views
Regions for naming areas on the UI so modules can add a view to a particular location.
The above 4 don't all have to be used but can easily be integrated in a MVVM /WPF application.
For example, would my "toolbar" be a
shell that contains regions that each
widget would populate?
Here you can have a region you create (you can derive from Region) that will manage the buttons on the toolbar. (I have used a region with regards to a Ribbon). A service can be exposed via an interface that each module can supply the command/image (what ever you have) that when it is clicked will create a ViewModel. You can do this inside the module's Initialisation.
Would each new window that is
displayed when a widget is clicked
also be its own shell with its own
region setup?
If each button opens a brand new window I would suggest introducing a common controller class that will create a generic use window and attach a view model that your module creates. No real need to use regions in this case unless you are gluing different views to a application window that stays open longer than the life of the view itself. The window in basic form can simply be this...
<Window ...>
<ContentControl Content="{Binding}" />
</Window>
Where within your controller it can do this...
public void DisplayView(ViewModel vm)
{
var window = new MyWindow { DataContext = vm };
window.Show();
}
The controller can be used within your module directly of wrapped within a service... although for testabilty a service and interface would be best. Make sure you have merged your module resources with the Applicaiton.Resources and use DataTemplate's to link your view to the view model.
My question is where will the mouse
click/move events, that are specific
to the chart in that view, be written?
Don't be afraid of code behind but you can in this case use EventToCommand attached behaviour that will route to a command on your viewmodel. MVVMLight toolkit has this which you can reuse if you want.
DI is very powerful and I encourage using it even without Prism as constructing your view models will be easier.
HTH
I think Prism will work great for you.
->would my "toolbar" be a shell that contains regions that each widget would populate?
Put a single region with an ItemsControl in the Shell
Create modules for each widget
Keep adding the widget modules to the same itemscontrol shell region.
The biggest advantage with this is that if you add more modules you don't need to change anything.
->Would each new window that is displayed when a widget is clicked also be its own shell with its own region setup?
No, you can use a 'WindowRegionAdapter' in the shell to create views for your widgets in separate windows.
->where will the mouse click/move events, that are specific to the chart in that view, be written?
You can use attached behaviors to bind events in your view to commands in the ViewModel purely in XAML. Google 'Blend behaviors' or 'attached bahaviors' for how you could go about doing it. There is no need to write any code behind for this.
To be honest I am only trying to give you the keywords you'd want to search to get all the information you need.
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