I am having difficulty in finding a relation between a given Module and Views(plain WPF user control) which has been Registered to different regions using this Module (in IModule Initialize() method).
When a Request comes to load a module IModuleManager.LoadModule is being used the first time to load the module. First time loading a module is not as issue.
Now, another request comes to load a module,which was already loaded so I can not use IModuleManager.LoadModule method, (User will just give ModuleName).
Now I have to find out what are the its Regions (need to clear them first) and its View (need to load them in there respective Regions).
So I need a map , kind of triplet, of Module-View-Region and create this triplet first time when IModuleManager.LoadModuleCompleted gets triggered. Later I can use this to find the regions and views.
Used IRegionViewRegistry.ContentRegistered but it just gives (Regions and Views). But no way to relate it to ModuleName(of Module Info) and IModuleManager.LoadModuleCompleted just gives ModuleInfo (no way to find out Regions and Views it uses)
Related
Please consider following Backbone application structure:
AppView
Subview
FirstSubviewInQuestion
Subview
Subview
SecondSubviewInQuestion
Application view creates and stores a collection of special items. At a certain time the first and the second subview needs to get access to that collection. Now what is the best way to pass the collection it to them?
I myself see some ways, yet each has a downside:
1) Create instance of that collection not inside the App View but even more globally and then pass it around as dependency (project uses RequireJS; so it would be passed to AppView and both Subviews).
Downsides: app view is supposed to be the top most element in application. Yet suddenly we have some instances of collections floating above.
2) Or I can do following:
// some subview
var collection = {};
Backbone.trigger( "item:getSpecialItems", collection);
// now the collection has data
// app view
this.listenTo( "item:getSpecialItems", function(obj) {
// copy collection to passed object
_.extend(obj, this.specialCollection);
});
Downsides: we are triggering a global event. We know that only the app view would respond, but it feels like a bad design. Plus, this way to pass the collection seems like a hack.
Maybe there are some other clever ways to do it?
I would say #1.
app view is supposed to be the top most element in application
Right, but you're talking about (I think) a Collection, not a View; the two are totally separate parts of your application (in MVC the first is the "M" and the second is the "V"). By definition, if your views are driven by your data, the data must be "higher" (in the dependency tree) than any view, so I don't see anything wrong with that approach.
If your goal is to get a shared instance of the collection, my approach would be to pass that down from the parent to "subview" and from subview into its children. However, I wouldn't necessarily use require to pass around a singleton of this collection.
You could also pull out all of the logic from the view regarding the special methods for "creation and storage of special objects" into a helper class whose sole domain is just this. That helper then becomes a utility available from outside the view hierarchy, perhaps even globally or via require.
I`m learning the concepts of composite applications.
I created prism application using unity container.
One of my regions configed as content control - In this Region, I want show just single view.
I`m using view injection in the next way:
object lastView;
// View injection
IRegion region = regionManager.Regions["MainRegion"];
var ordersView = container.Resolve<OrdersView>();
lastView = ordersView;
region.Add(ordersView, "OrdersView");
region.Activate(ordersView);
This the views in this region are switched frequently.
Before Im switching view Im using region.remove(lastView)
and than adding the next view like the code above.
Im not sure that its a good implementation, I have a few questions:
When I`m using region.remove method, Is the removed view being disposed?
Because if not after long run I will have serious memory leaks.
What is the best way implement single view in a region while avoiding memory leaks?
Thanks
By memory leaks I guess you're talking about whether the Garbage Collector is going to collect that view or not - e.g. is the container still referencing it when you remove it.
The decision on whether to keep a reference of the object after it's resolved is based on the type of the LifeTime Manager you used when you registered that object.
To answer your question shortly - The default LifeTime manager used with RegisterType is the TransientLifetimeManager, in which Unity creates a new instance of the requested type for each call to the Resolve or ResolveAll method.
What you're probably looking for is the ExternallyControlledLifetimeManager:
This lifetime manager allows you to register type mappings and existing objects with the container so that it maintains only a weak reference to the objects it creates when you call the Resolve or ResolveAll method or when the dependency mechanism injects instances into other classes based on attributes or constructor parameters within that class. This allows other code to maintain the object in memory or dispose it and enables you to maintain control of the lifetime of existing objects or allow some other mechanism to control the lifetime.
If you want to control the lifetime of your views, consider using the RegisterType with this LifeTime Manager.
Also, according to this article - The only lifetime managers which calls Dispose on resolved instances are ContainerControlledLifetimeManager (which creates singelton instances) and HierarchicalLifetimeManager. In these cases, the Dispose is only called when the lifetime manager is disposed.
I'm really new to the MVC pattern in Ext.
I have a tabpanel with multiple instances of the same component (let's call it product), each should call the server when it's opened, with an id parameter.
Right now, in order to create these tabs - I use this in the Product controller
Which creates a new instance of a view, but I feel like it's really incorrect.
createMainView: function (opts) {
return Ext.widget("productDisplay", opts);
}
I call it from my "main" controller, like this:
var tab = this.application.getController("Products")
.createMainView({ productId : id, closable: true })
tabs.add(tab);
tabs.setActiveTab(tab);
What's the correct way to properly use multiple instances of a view, each having an instance of one store and behavior (via the controller).
Can I use one named store for them (with a js file under app/store/product.js)?
Should I manually call load on the store from the controller (to pass the productId), or is there a nicer way?
It's kind of very broad and interesting question which require big and thorough explanation (which you can find btw on the Sencha.com in their guides and manuals). I would like highlight couple points so you have something to start with:
Stores are usually global objects. You don't keep two instances of one store in general. You can use filtering (local or remote) if you need to present information from the that store in several different views. The only time you would need to clone store is if you want to present different information from that store in 2+ different views at the same time.
Controllers are usually spawned by main application object. You don't have to do anything special - just list them in the controllers: [] property. And then spawed when application is launched (before their views are created and rendered). Keep that in mind.
If you have modal view - it's ok to create it manually and either re-use it or destroy and re-create later. You can add filtering and loading to controller which creates these views. And you can re-use same view/controller objects for different tabs if you want.
If your views are presenting one instance of an object (like one product is displayed on each tab) - don't attach stores to those views. Just pass them individual model (record).
I would recommend creating the stores that relate only to that view instance inside of the view's initComponent method.
Your controller's control handlers should be coded in a way that they can differentiate which view dispatched the event. This should not be too difficult because almost all view events contain a reference to the component which fired the event. You could then use the relative query selectors, e.g.: myEventFiringComponent.up('anotherComponent') or myEventFiringComponent.down('anotherComponent') to get a handle on a different component in the same view if you need to.
Please see this post for a full explanation.
my first real (not test) NHibernate/Castle.ActiveRecord project is developing quickly.
I am working with NHibernate/Castle.ActiveRecord about one month now but still have not a real idea how to handle Sessions in my WindowsForms application.
The common handling-methods seam not to work for me:
SessionPerRequest, SessionPerConversation, etc. all only work for WebApplications, etc.
SessionPerApplication is not recomanded/highly dangerous when I am correct
SessionPerThread is not very helpfull, since I either have only one thread, the WindowsForms-thread, or for each button-click a new thread. The first thing would make my applicaton use too much memory and to hold old objects in the memmory. With worker-threads for ech button click I would disable lazy-loading, since my loaded objects would live longer then the thread.
SessionPerPresenter is not working as well, because it is common, that I open a "sub-presenter" in a form to let the user search/load/select some referenced objects (foreigen key) and of cause the presenter is destroyed - what means session closed - but the object used in the "super-presenter" to fill the referencing property (foreigen key).
I've used google and bing for hours and read a lot, but only found one good website about my case: http://msdn.microsoft.com/en-us/magazine/ee819139.aspx . There SessionPerPresenter is used, but to a "sub-presenter" it is only given the id, not the entire object! And it seams that there are no foreigen-keys in this example and no scenari in wich a object is returned to a "super-presenter".
Qestions
Is there any other method of session handling for windowsforms/desktop-application?
I could add a session-property or a session-constructor-parameter to all of my presenters, but it feels not right to have session-handling all over my ui-code.
When an Exception occures NHibernate want's me to kill the session. But if it is 'only' a business-logic exception and not an NHibernate-Exception?
Example
I am trying to make an example the covers most of my problem.
// The persisten classes
public class Box
{
public virtual int BoxId{get;set;}
public virtual Product Content{get;set;}
...
}
public class User
{
public virtual int UserId{get;set;}
public virtual IList<Product> AssigenedProducts{get;set;}
...
}
public clas Product
{
public virtual int ProductId{get;set;}
public virtual string PrductCode{get;set;}
}
.
// The presenter-classes
public class ProductSearchPresenter : SearchPresenter<Product> { ... }
public class ProductEditPresenter : EditPresenter<Product> { ... }
public class UserSearchPresenter : SearchPresenter<User> { ... }
public class UserEditPresenter : EditPresenter<User> { ... }
public class BoxSearchPresenter : SearchPresenter<Box> { ... }
public class BoxEditPresenter : EditPresenter<Box> { ... }
// The search-presenters allow the user to perform as search with criterias on the class defined as generic argument and to select one of the results
// The edit-presenters allow to edit a new or loaded (and given as parameter) object of the class defined as generic argument
Now I have the following use-cases, wich all can be performed in the same application at the same time asyncronous (the use simply switchs between the presenters).
using an instance of BoxSearchPresenter to search and select a object
part of this usecase is to use an instance of the ProductSearchPresenter to fill a criteria of the BoxSearchPresenter
part of this usecase is to use an instance of the BoxEditPresenter to edit and save the selected object of the BoxSearchPresenter-instance
using an instance of UserSearchPresenter to search and select a object
part of this usecase is to use an instance of the UserEditPresenter to edit and save the slected object of the UserSearchPresenter
part of this usecase is to use a ProductSearchPresenter to search and select objects that will be added to User.AssignedProducts.
Using an instance of ProductSearchPresenter to search and select a object.
part of this usecase is to use an instance of ProductEditPresenter to edit and save a selected object of the ProductSearchPresenter.
It's only a small collection of usecases, but there are allready a lot of the problems I have.
UseCase 1. and 2. run at the same time in the same ui-thread.
UseCase 1.1. and 2.2. return there selected objects to other presenters that use this objects longer then the presenters exist that have loaded the object.
UseCase 3.1. might alter a object loaded from 2.2./1.1. before 3.1. was started, but when 2.2./1.1. is commited before 3.1. is finished the object would be saved and it would not be possible to "rollback" 3.1.
Here is just a short view of what I found best to fit into our WinForms application architecture (based on MVP).
Every presenter is constructor dependent on repositories which it needs, for example if you have InvoicePresenter then you have InvoiceRepository as dependency, but you will probably have CustomerRepository and many others depending on complexity (CustomerRepsitory for loading all customers into the customers combobox if you want to change customer of the invoice, stuff like that).
Then, every repository has a constuctor argument for UnitOfWork. Either you can abstract the session with UnitOfWork pattern, or you can have your reporitories depend on ISession.
Everything is wired together by IoC container, where we create presenters based on "context". This is a very simple concept, context is per presenter and all sub presenter, which in turn we create as composite block of more complex presenters to reduce complexitiy (if for example you have multiple tabs of options to edit some entity or something).
So, in practice, this context is 90% time form based, because one form is at least one presenter / view.
So to answer your questions:
Session per presenter and session per conversation (works with WinForms as well) are only really usable patterns here (and opening closing sessions all over the place, but not really good way to handle that)-
this is best solved by making repositories depend on session, not presenters. You make presenters depend on repositories, repositories depend on session, and when you create all, you give them common session; but as I state again, this is only practical when done in contexts. You cannot share session for presenter editing invoices and another presenter editing customers; but you can share session when editing invoice via main presenter and invoice details and invoice notes sub presenter.
Please clarify, didn't understand this...
I need to make sure certain essential data are loaded before a module is loaded and shown on screen. considering the async nature of data loading in silverlight, I was wondering if there is a pattern I should follow to load my data (like an event on the module or the bootstrap to hook into, or a method to override)...
you can set module InitializationMode to OnDemand and once you have your data call moduleManager.LoadModule("YourModuleName"); as described here.
There's another alternative as well. If you know you're going to need the module, and the data is statically stored inside another module, you can establish dependencies:
ModuleCatalog m = new ModuleCatalog();
...
m.AddModule(typeof(PersonModule.PersonModule), "ModuleA");
In this scenario, your module in question would establish a dependency on whatever module has the data, and this would ensure that the data is loaded before-hand.