dependency-injection - Windows Phone 7 的依赖注入(inject)

Question

我试图在我的 Windows Phone 7 项目中使用 Unity 2.0 beta 2 for Silverlight，但我一直遇到这个崩溃:

Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.DynamicMethodConstructorStrategy() + 0x1f 字节

Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.DynamicMethodConstructorStrategy() + 0x1f 字节 mscorlib.dll!System.Reflection.RuntimeConstructorInfo.InternalInvoke(System.Reflection.RuntimeConstructorInfo rtci = {System.Reflection.RuntimeConstructorInfo} , System.Reflection.BindingFlags invokeAttr = Default, System.Reflection.Binder binder = null, object parameters = {object[0]}, System.Globalization.CultureInfoculture = null, bool isBinderDefault = false, System.Reflection.Assembly caller = null, bool verifyAccess = true, ref System.Threading.StackCrawlMark stackMark = LookForMyCaller)
mscorlib.dll!System.Reflection.RuntimeConstructorInfo.InternalInvoke(object obj = null, System.Reflection.BindingFlags invokeAttr = Default, System.Reflection.Binder binder = null, object[] parameters = {object[0]}, System.Globalization .CultureInfo 文化 = null，引用 System.Threading.StackCrawlMark stackMark = LookForMyCaller) + 0x103 字节
mscorlib.dll!System.Activator.InternalCreateInstance(System.Type type = {Name = "DynamicMethodConstructorStrategy"FullName = "Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy"}, bool nonPublic = false, ref System.Threading.StackCrawlMark stackMark = LookForMyCaller) + 0xf0 字节 mscorlib.dll!System.Activator.CreateInstance() + 0xc 字节
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.ObjectBuilder2.StagedStrategyChain.AddNew(Microsoft.Practices.Unity.ObjectBuilder.UnityBuildStage stage = Creation) + 0x1d 字节
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityDefaultStrategiesExtension.Initialize() + 0x6c 字节
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityContainerExtension.InitializeExtension(Microsoft.Practices.Unity.ExtensionContext context = {Microsoft.Practices.Unity.UnityContainer.ExtensionContextImpl}) + 0x31 字节
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityContainer.AddExtension(Microsoft.Practices.Unity.UnityContainerExtension 扩展 = {Microsoft.Practices.Unity.UnityDefaultStrategiesExtension}) + 0x1a 字节
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityContainer.UnityContainer() + 0xf 字节

以为我可以解决它，我尝试了几件事，但无济于事。

事实证明这是一个相当基本的问题，我假设 Windows Phone 7 是 Silverlight 3 + 其他一些东西是错误的。这个page描述 Mobile Silverlight 和 Silverlight 3 之间的区别。

特别感兴趣的是:

The System.Reflection.Emit namespace is not supported in Silverlight for Windows Phone.

这正是 Unity 在手机上崩溃的原因， DynamicMethodConstructorStrategy类使用 System.Reflection.Emit相当广泛...

所以问题是， Windows Phone 7 有什么 Unity 替代品？

Answer 1

因此，本着回答我自己问题的精神，我整理了一个简单的 DI 容器(使用 Activator.CreateInstance 进行实例化)。所有这些都是支持类型注册和实例注册。

似乎正在做这项工作。以后会担心性能。

public class DuplicateRegistrationException : Exception {
    public DuplicateRegistrationException() { }
    public DuplicateRegistrationException(string message) : base(message) { }
    public DuplicateRegistrationException(string message, Exception inner) : base(message, inner) { }
}

public interface IDIContainer {
    void Register<TIntf, TClass> () where TIntf: class where TClass : TIntf;
    TIntf Resolve<TIntf>() where TIntf : class;
    void RegisterInstance<TIntf>(TIntf instance);
}

public class DIContainer :  IDIContainer{

    Dictionary<Type, Type> m_TypeRegistrations;
    Dictionary<Type, object> m_InstanceRegistrations;

    public DIContainer() {
        m_TypeRegistrations = new Dictionary<Type, Type>();
        m_InstanceRegistrations = new Dictionary<Type, object>();
    }

    #region IDIContainer Members

    public void Register<TIntf, TClass>()
        where TIntf : class
        where TClass : TIntf {
            if(DoesRegistrationExist<TIntf>())
                throw new DuplicateRegistrationException("Can only contain one registration per type");
            m_TypeRegistrations.Add(typeof(TIntf), typeof(TClass));
    }

    public TIntf Resolve<TIntf>() where TIntf : class {
        return Resolve(typeof(TIntf)) as TIntf;
    }

    private object Resolve(Type type) {
        if(!m_TypeRegistrations.ContainsKey(type)) {
            if(!m_InstanceRegistrations.ContainsKey(type))
                throw new NotSupportedException("Cannot find registration for type " + type.FullName + ".");
            else
                return m_InstanceRegistrations[type];
        } else {
            var createdType = m_TypeRegistrations[type];

            ConstructorInfo[] constructors = createdType.GetConstructors();
            ConstructorInfo mostSpecificConstructor = null;
            foreach(var c in constructors) {
                if(mostSpecificConstructor == null || mostSpecificConstructor.GetParameters().Length < c.GetParameters().Length) {
                    mostSpecificConstructor = c;
                }
            }

            List<object> constructorParameters = new List<object>();
            foreach(var a in mostSpecificConstructor.GetParameters()) {
                constructorParameters.Add(Resolve(a.ParameterType));
            }

            return Activator.CreateInstance(createdType, constructorParameters.ToArray());
        }
    }

    private bool DoesRegistrationExist<T>() {
        return m_InstanceRegistrations.ContainsKey(typeof(T)) || m_TypeRegistrations.ContainsKey(typeof(T));
    }

    public void RegisterInstance<TIntf>(TIntf instance) {
        if(DoesRegistrationExist<TIntf>()) {
            throw new DuplicateRegistrationException("Can only contain one registration per type");
        }
        m_InstanceRegistrations.Add(typeof(TIntf), instance);
    }


    #endregion