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Dependency Injection framework for WinRT - Widows 8 application

Am inceput sa lucrez la o aplicatie metro style pentru Windows 8. Toate bune si frumoase pana am ajuns in momentul in care am dorit sa folosesc un framework de DI. Cum inca vorbim de VS2011 BETA si un API redus pentru aplicatile metro style, m-am trezit ca nici un framework consacrat precum Unity, Ninject, Windsor nu a fost portat inca pentru acest tip de aplicatii.
Cauza pentru care inca nu a fost inca portat este destul de clara. Pentru aplicatiile metro style pentru Windows 8, nu folosim .NET Core si un .NET Framework, care are un API mult mai sarac. Multe functionalitati, mai ales din zona reflection lipsesc.
Am gasit pe codeplex un framework pentru WinRT, care se numea MetroIoc. http://metroioc.codeplex.com/
Parea destul de usor de folosit, asa ca am zis sa ii dau o sansa, sa vad daca functioneaza si daca este ce caut. API este foarte asemanator cu cel de la Unity, asa ca din punct de vedere a setup-ului la container l-am putut face foarte repede.
Am pregatit si o metoda de teste si surpriza. Testul nici macar nu a putut sa ruleze. A crapat procesul care rula testele. M-am mai jucat putin cu acesta, sperand ca poate sunt eu de vina, dar nu am reusit sa il fac sa functioneze.
Aplicatia la care lucrez fiind o aplicatie destul de simpla am zis ca cel mai bine este sa nu ma complic si sa risc sa am probleme in viitor. Revin la clasica proprietate "Instance" din fiecare clasa care vreau sa fie unica per proces.
O alta solutie ar fi sa imi definesc un ObjectFactory care sa imi tina in spate o lista statica de instante. M-am gandit ceva simplu, asemanator cu codul de mai jos:
public class ObjectFactory
{
    public static ObjectFactory Instance { get; private set; }

    static ObjectFactory()
    {
        Instance = new ObjectFactory();
    }

    private readonly Dictionary<Type, object> _objMapping;


    public ObjectFactory()
    {
        _objMapping=new Dictionary<Type, object>();
    }
       
    public void AddObject<TType>(TType instance)
    {
        Type itemType = typeof (TType);
        RemoveObject(itemType);

        _objMapping.Add(itemType,instance);
    }

    private void RemoveObject(Type itemType)
    {
        if (_objMapping.ContainsKey(itemType))
        {
            _objMapping.Remove(itemType);
        }
    }

    public TType GetInstance<TType>()
    {
        return (TType)_objMapping[typeof(TType)];
    }
}

Mai mult de atata nu vreau sa fac in momentul de fata, deoarece ma astept ca in viitor o sa apara un mecanism de DI si pentru WinRT, si nu are rost sa incerc sa reinvetenz roata.

Comments

  1. Interesant :) Ma asteptam ca macar MEF sa existe pe WinRT/Metro..
    Cat despre ObjectFactory, seamana destul de mult cu IServiceLocator (http://commonservicelocator.codeplex.com/)
    care desi nu e "true" DI si multi il considera un antipattern, e util in unele cazuri..

    ReplyDelete
    Replies
    1. Implementarea este foarte asemanatoare cu IServiceLocator. Nu am vrut sa reinvetez roata.
      O sa apara pana in toamna si suport pentru DI, dar trebuie sa avem rabdare. Suntem inca in BETA, care din pacate nu e deloc perfect.

      Delete
    2. Ce-i drept, DI nu e decat un pattern, se poate implementa si fara un IoC container si fara service locator.

      Delete
  2. Nu cumva e suficient cît ai acolo? Chiar e nevoie de 'un framework' dedicat pentru așa ceva?
    (signed: a non-believer)

    ReplyDelete
    Replies
    1. In momentul de fata e mai mult decat e nevoie.
      Si ai 100% dreptate, un DI trebuie folosit cu cap si echilibrat.

      Delete
  3. Se pare ca Autofac are suport pentru Metro. Vezi la http://groups.google.com/group/autofac/browse_thread/thread/ca89209cbaffb61a/deb4e460a687b164?show_docid=deb4e460a687b164&pli=1

    Numai bine,
    Nelu

    ReplyDelete

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