I'ave been studying this blog post from Lauren Bugnion on MVVM light IOC containers and I there is one thing that really confuses me.
Here's a link to the blog post
MVVM light IOC containers blog
I dont wanna quote the entire thing so I'm only going to include the snippet that I have a hard time understanding.
public class ViewModelLocator
{
static ViewModelLocator()
{
ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
if (ViewModelBase.IsInDesignModeStatic)
{
SimpleIoc.Default.Register<IRssService, Design.DesignRssService>();
}
else
{
SimpleIoc.Default.Register<IRssService, RssService>();
}
SimpleIoc.Default.Register<INavigationService, NavigationService>();
SimpleIoc.Default.Register<MainViewModel>();
}
public MainViewModel Main
{
get
{
return ServiceLocator.Current.GetInstance<MainViewModel>();
}
}
}
Now I understand the static constructor and everything but I can't wrap my head around the
public MainViewModel Main
{
get
{
return ServiceLocator.Current.GetInstance<MainViewModel>();
}
}
Is this function even accessible? and how?
Thanks! :)
Yes, it is accessible whenever you have an instance of ViewModelLocator. For example, you can instantiate an instance in App.xaml and it will be accessible via StaticResource.
Related
I have the following class which is my view model (this is very simple right now, but it will contain a chunk more logic eventually):
public class IndicoTalk : ITalk
{
private Talk _talk;
public IndicoTalk(Talk t)
{
this._talk = t;
}
public string Title
{
get { return _talk.Title; }
}
}
Now, I have a reactive ui view for this guy:
public sealed partial class TalkView : UserControl, IViewFor<ITalk>
{
public TalkView()
{
this.InitializeComponent();
this.Bind(ViewModel, x => x.Title, y => y.TalkTitle.Text);
}
Note that the IViewFor is for ITalk, not IndicoTalk. This is because I can have other types of talk, and they will all fit into the same view.
And I register this ViewModel in my App start up:
Locator.CurrentMutable.Register(() => new TalkView(),
typeof(IViewFor<IWalker.DataModel.Inidco.IndicoMeetingRef.IndicoTalk>));
Finally, in another viewmodel I have a ReactiveList which contains a bunch of these IndicoTalks's. Of course, when I bind this to a ListBox, ReactiveUI fails to find the view. If I switch to IViewFor then everything works just fine.
What is the proper way to gently redirect the view resolution in this case?
A half-way solution: leave all code above the same, but put in the IViewFor ITalk instead of IndicoTalk. This works, but means I will have to register with Splat (the CurrentMutable call above) every ViewModel that inherrits from ITalk. I'd love to avoid that if possible!
Many thanks!
So, why not just do:
Locator.CurrentMutable.Register(() => new TalkView(), typeof(IViewFor<ITalk>));
I am completely new to Actionscript and Adobe Flash CS6 and for a little bit of fun I have decided to try and make a little game. I had a few newbie (or noob-y) questions to ask about a general implementation approach.
The documentation I've been reading so far suggests creating a new flash project, and then create a document class so:
package {
import flash.display.MovieClip;
public class MyMainClass extends MovieClip {
public function MyMainClass() {
}
}
}
and I am wondering if I use this MainClass to code the whole game or include actionscript within a scene and have multiple scenes, or some combination of both.
Lets say I had a wanted 5 Levels in my game, would I do something like:
package {
import flash.display.MovieClip;
public class MyMainClass extends MovieClip {
public function MyMainClass() {
StartLevel1();
StartLevel2();
StartLevel3();
StartLevel4();
StartLevel5();
}
public function StartLevel1() {
// Do something
}
public function StartLevel2() {
// Do something
}
public function StartLevel3() {
// Do something
}
public function StartLevel4() {
// Do something
}
public function StartLevel5() {
// Do something
}
}
}
or create 5 scenes with actionscript in each scene?
Can anyone provide me with a bit of a starting point?
Thanks
I don't know of anyone who has anything good to say about scenes.
However, as you intuit, the timeline itself is a wonderful tool for managing the state of your Flash assets over time. If you use it, you also get the hidden advantage that you don't have to download 100% of your file to be able to use it (so you can reduce or even eliminate the need for a preloader by unchecking "Export in frame N" on your library symbols.
Lars has quite rightly pointed out that there are very few developers who understand this technique, and I know of exactly one who can and will help people who are interested in exploring this technique. That person is helping you right now. So if you choose to go that way, keep in mind you are mostly on your own except if I happen to notice your post and respond to it.
I am not in favor of timeline scripts, with a very few exceptions. What I suggest is a "both and" approach, where you use a Document Class to control timeline instances.
Your document Class might look something like this:
public class Game extends MovieClip {
protected var _level:ILevel;//Interface your Level MovieClips will implement
protected var levelController:LevelController = new LevelControler();
protected var currentLevel:int;
protected var maxLevels:int = 5;
public function Game() {
levelController.addEventListener(LevelEventKind.LEVEL_COMPLETE, nextLevel);
levelController.addEventListener(LevelEventKind.LEVEL_FAILED, gameOver);
startLevel(currentLevel);
}
public function startLevel(levelNumber:int):void {
goToLabel('Level' + String(levelNumber));
}
public function get level():ILevel {
return _level;
}
public function set level(value:ILevel):void {
_level = value;
//internally, this should release all listeners to the last
//level object (if any) so you don't get a memory leak
levelController.level = _level;
}
protected function nextLevel(e:Event):void {
if (currentLevel < maxLevels) {
startLevel(++currentLevel);
} else {
//do you won logic here
}
}
protected function gameOver(e:Event):void {
//do bombed out logic here
}
protected function goToLabel(label:String):void {
for each (var frameLabel:FrameLabel in currentLabels) {
if (frameLabel.name==label) {
//if your swf is media-heavy, may want to check that frame
//is loaded if you chose to reduce/eliminate preloader
goToAndStop(label);
return;
}
}
trace('no such label as', label);
}
}
What this gets you is a game where you can change how the different levels look without changing a single line of ActionScript, and you can change how they work by assigning different Base Classes that implement ILevel slightly differently. You can also change your functionality by swapping out different flavors of LevelController, but your Main Document Class (Game in this instance) would be aware of this change (wheras the other changes could be made without altering Game at all).
I have a Service that need inject more than one provider, see below for example. How to use Unity to implement this feature?
public class MyService: IMyService
{
public MyService(IEnumerable<Provider> Providers);
}
I know this is an old question, but maybe this will help someone else that stumbles upon this.
As long as you register the implementations with a specific name, this is possible to easily inject. You will then get all registered implementations.
public class MyService: IMyService
{
public MyService(IProvider[] providers)
{
// Do something with the providers
}
}
Just make sure to inject them as an array. Unity will understand this. And when you register them you can register them as such:
container.RegisterType<IProvider, FooProvider>("Foo");
container.RegisterType<IProvider, BarProvider>("Bar");
One way is to inject the UnityContainer itself, and then resolve all the Providers you need:
public class MyService : IMyService
{
public class MyService(IUnityContainer iocContainer)
{
var providers = iocContainer.ResolveAll<IProvider>();
}
}
The only thing you will need to do is register the UnityContainer with itself somewhere on setup:
unityContainer.Register<IUnityContainer>(unityContainer, new ContainerControllerLifetimeManager());
I am looking for some help and I hope that some good soul out there will be able to give me a hint :)
I am building a new application by using MVVM Light. In this application, when a View is created, it instantiates the corresponding ViewModel by using the MEF import.
Here is some code:
public partial class ContractEditorView : Window
{
public ContractEditorView ()
{
InitializeComponent();
CompositionInitializer.SatisfyImports(this);
}
[Import(ViewModelTypes.ContractEditorViewModel)]
public object ViewModel
{
set
{
DataContext = value;
}
}
}
And here is the export for the ViewModel:
[PartCreationPolicy(CreationPolicy.NonShared)]
[Export(ViewModelTypes.ContractEditorViewModel)]
public class ContractEditorViewModel: ViewModelBase
{
public ContractEditorViewModel()
{
_contract = new Models.Contract();
}
}
Now, this works if I want to open a new window in order to create a new contract... or in other words, it is perfect if I don't need to pass the ID of an existing contract.
However let's suppose I want to use the same View in order to edit an existing contract. In this case I would add a new constructor to the same View, which accepts either a model ID or a model object.
"Unfortunately" the ViewModel is created always in the same way:
[Import(ViewModelTypes.ContractEditorViewModel)]
public object ViewModel
{
set
{
DataContext = value;
}
}
As far as I know, this invokes the standard/no-parameters constructor of the corresponding ViewModel at composition-time.
So what I would like to know is how to differentiate this behavior? How can I call a specific constructor during composition time? Or how can I pass some parameters during the Import?
I really apologize if this question sounds silly, but I have only recently started to use MEF!
Thanks in advance,
Cheers,
Gianluca.
You CAN do this. Check out the Messenger implementation in MVVM-Light. You can pass a NotificationMessage(Of Integer) to send the right ID to the view model. The view model has to register for that type of message, and load it when a message is sent.
MEF Imports by default only have a parameterless constructor.
I am learning about best practices in MVC2 and I am knocking off a copy of the "Who Can Help Me" project (http://whocanhelpme.codeplex.com/) off Codeplex. In it, they use Castle Windsor for their DI container. One "learning" task I am trying to do is convert this subsystem in this project to use StructureMap.
Basically, at Application_Start(), the code news up a Windsor container. Then, it goes through multiple assemblies, using MEF, in ComponentRegistrar.cs:
public static class ComponentRegistrar
{
public static void Register(IContainer container)
{
var catalog = new CatalogBuilder()
.ForAssembly(typeof(IComponentRegistrarMarker).Assembly)
.ForMvcAssembly(Assembly.GetExecutingAssembly())
.ForMvcAssembliesInDirectory(HttpRuntime.BinDirectory, "CPOP*.dll") // Won't work in Partial trust
.Build();
var compositionContainer = new CompositionContainer(catalog);
compositionContainer
.GetExports<IComponentRegistrar>()
.Each(e => e.Value.Register(container));
}
}
and any class in any assembly that has an IComponentRegistrar interface will get its Register() method run.
For example, the controller registrar's Register() method implementation basically is:
public void Register(IContainer container)
{
Assembly.GetAssembly(typeof(ControllersRegistrarMarker)).GetExportedTypes()
.Where(IsController)
.Each(type => container.AddComponentLifeStyle(
type.Name.ToLower(),
type,
LifestyleType.Transient ));
}
private static bool IsController(Type type)
{
return typeof(IController).IsAssignableFrom(type);
}
Hopefully, I am not butchering WCHM too much. I am wondering how does one do this with StructureMap? I'm assuming that I use Configure() since Initialize() resets the container on each call? Or, is tit a completely different approach? Do I need the MEF-based assembly scan, used to find all registrars and run each Register(), or is there something similar in StructureMap's Scan()?
Have a look at StructureMap's registries (http://structuremap.github.com/structuremap/RegistryDSL.htm). To control the lifecycle use something like:
For<ISomething>().Use<Something>().LifecycleIs(new SingletonLifecycle());
(Transient is the default).
When you bootstrap the container you can say:
ObjectFactory.Initialize(c => c.Scan(s => {
s.WithDefaultConventions();
s.LookForRegistries();
}
Feel dirty, answering my own question, but I did the following:
public class ControllerRegistrar : IComponentRegistrar
{
public void Register(IContainer container)
{
container.Configure(x =>
{
x.Scan(scanner =>
{
scanner.Assembly(Assembly.GetExecutingAssembly());
scanner.AddAllTypesOf<IController>().NameBy(type => type.Name.Replace("Controller", ""));
});
});
}
}
I am not 100% sure this is right, but it works. Pulled it primarily from the "Registering Types by Name" section of this StructureMap doc page.