Review the following code, where to take care of cases with both single and named binding for an interface, an abstract factory is used as suggested here
Parameterized Factories Using Ninject
Challenge here is, I need to introduce IEnumerable<T> bankingOperationList, instead of T bankingOperationList, since for named binding it will always use the abstract factory injection, Func<string,T> bankingOperationFunc, but if I don't use IEnumerable<T> suggested above it leads to exception, due to this for even non named single binding, I need to use something like:
bankingOperationList.FirstOrDefault().Withdraw(), even when I know there will only be one dependency.
Another challenge is, for some named bindings it has 30 - 40 bindings in few cases, which will be unnecessarily filled, when I can default T bankingOperationList to null, as it is not required. Please let me know, if the issue needs further clarification. Working Console project underneath.
public interface IBankingOperation
{
void Withdraw();
}
public class BankingOperationOne : IBankingOperation
{
public BankingOperationOne()
{
Console.WriteLine("Testing Constructor :: One :: Empty");
}
public void Withdraw()
{
Console.WriteLine("Money Withdrawl Operation One");
}
}
public class BankingOperationTwo : IBankingOperation
{
public BankingOperationTwo()
{
Console.WriteLine("Testing Constructor :: Two :: Empty");
}
public void Withdraw()
{
Console.WriteLine("Money Withdrawl Operation Two");
}
}
// Ninject Bindings
public class Bindings : NinjectModule
{
public override void Load()
{
Bind<IBankingOperation>().To<BankingOperationOne>()
.Named("A");
Bind<IBankingOperation>().To<BankingOperationTwo>()
.Named("B");
Bind<Func<string,IBankingOperation>>().ToMethod(ctx => name => ctx.Kernel.Get<IBankingOperation>(name));
}
}
public class BankTran<T> where T : IBankingOperation
{
private IEnumerable<T> bankingOperationList = null;
private Func<string,T> bankingOperationFunc;
public BankTran(IEnumerable<T> boList = null,
Func<string,T> boFunc = null)
{
bankingOperationList = boList;
bankingOperationFunc = boFunc;
}
public void DoOperation(string identifier = null)
{
if(bankingOperationFunc != null)
bankingOperationFunc(identifier).Withdraw();
else
bankingOperationList.FirstOrDefault().Withdraw();
Console.WriteLine("Transaction Successful ");
}
}
class Program
{
static void Main(string[] args)
{
var kernel = new StandardKernel();
kernel.Load(Assembly.GetExecutingAssembly()); // Load from Bindings (derived from NinjectModule)
var transaction = kernel.Get<BankTran<IBankingOperation>>();
transaction.DoOperation("A");
}
}
Edit 1, based on response by jbl
public interface IBankingOperation<T>
{
void Withdraw();
}
public class BankingOperationOne : IBankingOperation<TestOne>
{
public BankingOperationOne()
{
Console.WriteLine("Testing Constructor :: One :: Empty");
}
public void Withdraw()
{
Console.WriteLine("Money Withdrawl Operation One");
}
}
public class BankingOperationTwo : IBankingOperation<TestTwo>
{
public BankingOperationTwo()
{
Console.WriteLine("Testing Constructor :: Two :: Empty");
}
public void Withdraw()
{
Console.WriteLine("Money Withdrawl Operation Two");
}
}
public class TestOne { }
public class TestTwo { }
// Ninject Bindings
public class Bindings : NinjectModule
{
public override void Load()
{
Bind<IBankingOperation<TestOne>>().To<BankingOperationOne>().Named("A");
Bind<IBankingOperation<TestOne>>().To<BankingOperationOne>().Named("B");
Bind<IBankingOperation<TestOne>>().To<BankingOperationOne>().WhenInjectedInto(typeof(BankTran<TestOne>));
Bind<Func<string, IBankingOperation<TestOne>>>().ToMethod(ctx => name => ctx.Kernel.Get<IBankingOperation<TestOne>>(name));
Bind<IBankingOperation<TestTwo>>().To<BankingOperationTwo>();
}
}
public class BankTran<T> where T : class
{
private IBankingOperation<T> bankingOperation;
private Func<string, IBankingOperation<T>> bankingOperationFunc;
public BankTran(IBankingOperation<T> bo = null,
Func<string, IBankingOperation<T>> boFunc = null)
{
bankingOperation = bo;
bankingOperationFunc = boFunc;
}
public void DoOperation(string identifier = null)
{
if (bankingOperationFunc != null && identifier != null)
bankingOperationFunc(identifier).Withdraw();
else if (bankingOperation != null)
bankingOperation.Withdraw();
Console.WriteLine("Transaction Successful ");
}
}
class Program
{
static void Main(string[] args)
{
var kernel = new StandardKernel(new NinjectSettings { AllowNullInjection = true});
kernel.Load(Assembly.GetExecutingAssembly()); // Load from Bindings (derived from NinjectModule)
var transaction = kernel.Get<BankTran<TestOne>>("A"); // Not Working
// var transaction = kernel.Get<BankTran<TestOne>>(); // Working
transaction.DoOperation();
}
}
Assuming BankingOperationOne is your default behaviour,
adding the following line in your Load method should allow to replace the IEnumerable<T> with T in your BankTran constructor :
Bind<IBankingOperation>().To<BankingOperationOne>().WhenInjectedInto(typeof(BankTran<>));
Another solution would be to just define a named binding for default behaviour
Bind<IBankingOperation>().To<BankingOperationOne>().Named("__DefaultBehaviour");
then
public void DoOperation(string identifier = "__DefaultBehaviour")
{
if (bankingOperationFunc != null)
bankingOperationFunc(identifier).Withdraw();
Console.WriteLine("Transaction Successful ");
}
Edit :
You should use the Ninject.Extenstions.Factory nuget package.
Using this package, the following code seems to fullfill you requirements.
public interface IBankingOperation<T>
{
void Withdraw();
}
public interface IBankingOperationFactory<T>
{
IBankingOperation<T> GetBankingOperation(string name);
}
public class BankingOperationOne : IBankingOperation<TestOne>
{
public BankingOperationOne()
{
Console.WriteLine("Testing Constructor :: One :: Empty");
}
public void Withdraw()
{
Console.WriteLine("Money Withdrawl Operation One");
}
}
public class BankingOperationTwo : IBankingOperation<TestTwo>
{
public BankingOperationTwo()
{
Console.WriteLine("Testing Constructor :: Two :: Empty");
}
public void Withdraw()
{
Console.WriteLine("Money Withdrawl Operation Two");
}
}
public class TestOne { }
public class TestTwo { }
// Ninject Bindings
public class Bindings : NinjectModule
{
public override void Load()
{
Bind<IBankingOperation<TestOne>>().To<BankingOperationOne>().Named("A");
Bind<IBankingOperation<TestOne>>().To<BankingOperationOne>().Named("B");
Bind<IBankingOperation<TestOne>>().To<BankingOperationOne>().WhenInjectedInto(typeof(BankTran<TestOne>));
Bind<IBankingOperationFactory<IBankingOperation<TestOne>>>().ToFactory();
Bind<IBankingOperation<TestTwo>>().To<BankingOperationTwo>();
}
}
public class BankTran<T> where T : class
{
private IBankingOperation<T> bankingOperation;
private IBankingOperationFactory<T> _bankingOperationFactory;
public BankTran(IBankingOperation<T> bo = null,
IBankingOperationFactory<T> bankingOperationFactory = null)
{
bankingOperation = bo;
_bankingOperationFactory = bankingOperationFactory;
}
public void DoOperation(string identifier = null)
{
if (_bankingOperationFactory != null && identifier != null)
_bankingOperationFactory.GetBankingOperation(identifier).Withdraw();
else if (bankingOperation != null)
bankingOperation.Withdraw();
Console.WriteLine("Transaction Successful ");
}
}
class Program
{
static void Main(string[] args)
{
var kernel = new StandardKernel(new NinjectSettings { AllowNullInjection = true });
kernel.Load(Assembly.GetExecutingAssembly()); // Load from Bindings (derived from NinjectModule)
var transaction = kernel.Get<BankTran<TestOne>>();
transaction.DoOperation();
transaction.DoOperation("A");
transaction.DoOperation("B");
}
}
Related
In this example, I want to patch PatchTarget.QSingleton\<T\>.get_Instance().
How to get it done with Harmony or MonoMod?
Harmony:
"Unhandled exception. System.NotSupportedException: Specified method
is not supported."
MonoMod:
"Unhandled exception. System.ArgumentException: The given generic
instantiation was invalid."
Code snippet: (runnable with dotnetfiddle.net)
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Reflection.Emit;
using HarmonyLib;
namespace PatchTarget {
public abstract class QSingleton<T> where T : QSingleton<T>, new() {
protected static T instance = null; protected QSingleton() { }
public static T Instance { get {
if (instance == null) {
instance = new T();
Console.Write($"{typeof(T).Name}.Instance: impl=QSingleton");
}
return instance;
} }
}
}
namespace Patch {
public class TypeHelper<T> where T : PatchTarget.QSingleton<T>, new() {
public static T InstanceHack() {
Console.Write($"{typeof(T).Name}.Instance: impl=InstanceHack");
return null;
}
}
public static class HarmonyPatch {
public static Harmony harmony = new Harmony("Try");
public static void init() {
var miOriginal = AccessTools.Property(typeof(PatchTarget.QSingleton<>), "Instance").GetMethod;
var miHack = AccessTools.Method(typeof(TypeHelper<>), "InstanceHack");
harmony.Patch(miOriginal, prefix: new HarmonyMethod(miHack));
}
}
public static class MonoModPatch {
public static MonoMod.RuntimeDetour.Detour sHook;
public static void init() {
var miOriginal = AccessTools.Property(typeof(PatchTarget.QSingleton<>), "Instance").GetMethod;
var miHack = AccessTools.Method(typeof(TypeHelper<>), "InstanceHack");
sHook = new MonoMod.RuntimeDetour.Detour(miOriginal, miHack);
}
}
}
class Program {
public static void Main() {
Patch.HarmonyPatch.init();
// Patch.MonoModPatch.init();
Console.WriteLine($"done");
}
}
After some trial and error, I got something working, but not the reason behind it.
Both Harmony and MonoMod.RuntimeDetour can hook with the typeof(QSingleton<SampleA>).GetMethod(), but not typeof(QSingleton<>).GetMethod().
Harmony output is unexpected.
Harmony attribute annotation doesn't seem to work.
Generating IL seems useless due to the potential lack of TypeSpec for generic.
Questions:
What is the difference between QSingleton<>.Instance and QSingleton<SampleA>.Instance in the sample?
I would guess that <>.Instance is MethodDef, while <SampleA>.Instance is TypeSpec.MemberRef.
Why does Harmony/MonoMod.RuntimeDetour need TypeSpec.MemberRef? For generating redirection stub?
Is it possible to fix the hook under Harmony?
Can Harmony/MonoMod generates "ldtoken <TypeSpec>" if TypeSpec already exists?
Can Harmony/MonoMod dynamically generates necessary TypeSpec for generics?
Code snippet: (runnable with dotnetfiddle.net)
using System;
using HarmonyLib;
namespace PatchTarget {
public abstract class QSingleton<T> where T : QSingleton<T>, new() {
protected static T instance = null; protected QSingleton() { }
public static T Instance { get {
if (instance == null) {
instance = new T();
Console.WriteLine($"{typeof(T).Name}.Instance: impl=QSingleton");
}
return instance;
} }
}
public class SampleA : QSingleton<SampleA> {
public SampleA() { Console.WriteLine("SampleA ctor"); }
}
public class SampleB : QSingleton<SampleB> {
public SampleB() { Console.WriteLine("SampleB ctor"); }
}
}
namespace Patch {
public class TypeHelper<T> where T : PatchTarget.QSingleton<T>, new() {
public static T InstanceHack() {
Console.WriteLine($"{typeof(T).Name}.Instance: impl=InstanceHack");
return null;
}
// For Harmony as Prefix, but attribute does not work.
public static bool InstanceHackPrefix(T __result) {
Console.WriteLine($"{typeof(T).Name}.Instance: impl=InstanceHack");
__result = null;
return false;
}
}
public static class HarmonyPatch {
public static Harmony harmony = new Harmony("Try");
public static void init() {
// Attribute does not work.
// Transpiler does not work because the lack of TypeSpec to setup generic parameters.
var miOriginal = AccessTools.Property(typeof(PatchTarget.QSingleton<PatchTarget.SampleB>), "Instance").GetMethod;
var miHack = AccessTools.Method(typeof(TypeHelper<PatchTarget.SampleB>), "InstanceHackPrefix");
harmony.Patch(miOriginal, prefix: new HarmonyMethod(miHack));
}
}
public static class MonoModPatch {
public static MonoMod.RuntimeDetour.Detour sHook;
public static void init() {
var miOriginal = AccessTools.Property(typeof(PatchTarget.QSingleton<PatchTarget.SampleB>), "Instance").GetMethod;
var miHack = AccessTools.Method(typeof(TypeHelper<PatchTarget.SampleB>), "InstanceHack");
sHook = new MonoMod.RuntimeDetour.Detour(miOriginal, miHack);
}
}
}
class Program {
public static void Main() {
_ = PatchTarget.SampleA.Instance;
// MonoMod works (replaces globally).
// Harmony hooks, but in an expected way (T becomes SampleB, not 1st generic type parameter).
// try { Patch.HarmonyPatch.init(); } catch (Exception e) { Console.WriteLine($"Harmony error: {e.ToString()}"); }
try { Patch.MonoModPatch.init(); } catch (Exception e) { Console.WriteLine($"MonoMod error: {e.ToString()}"); }
_ = PatchTarget.SampleB.Instance;
_ = PatchTarget.SampleA.Instance;
Console.WriteLine($"done");
}
}
MonoMod.RuntimeDetour Output:(Work as intended)
SampleA.Instance: impl=QSingleton
SampleB.Instance: impl=InstanceHack
SampleA.Instance: impl=InstanceHack
Harmony Output:(Broken <T>)
SampleA.Instance: impl=QSingleton
SampleB.Instance: impl=InstanceHack
SampleB.Instance: impl=InstanceHack
I can do this with StructureMap using Constructor Injection. However I cannot find a way to do this with Simple Injector. Here is some code that illustrates this (sorry for the length)
I've looked at the lambda in the Register method, but can't seem to understand how to call a single application wide instance of the container to get the one instance I need.
These are the object graphs I wish to construct:
var bannerTalker =
new LoudMouth(
new ConsoleShouter(), // Implements IConsoleVoicer
new ObnoxiousBannerGenerator());
var plainTalker =
new TimidSpeaker(
new ConsoleWhisperer()); // Implements IConsoleVoicer
Here's the code:
``` c#
public interface IConsoleVoicer
{
void SaySomething(string whatToSay);
}
public class ConsoleWhisperer : IConsoleVoicer
{
public void SaySomething(string whatToSay)
{
Console.WriteLine(whatToSay?.ToLower());
}
}
public class ConsoleShouter : IConsoleVoicer
{
public void SaySomething(string whatToSay)
{
Console.WriteLine(whatToSay?.ToUpper());
}
}
public interface IBannerGenerator
{
string GetBanner();
}
public class ObnoxiousBannerGenerator : IBannerGenerator
{
public string GetBanner()
{
return "OBNOXIOUS";
}
}
public interface IBannerTalker
{
void SayWithBanner(string somethingToSay);
}
public class LoudMouth : IBannerTalker
{
private IConsoleVoicer Voicer { get; set; }
private IBannerGenerator BannerGenerator { get; set; }
public LoudMouth(
IConsoleVoicer concoleVoicer, IBannerGenerator bannerGenerator)
{
Voicer = concoleVoicer;
BannerGenerator = bannerGenerator;
}
public void SayWithBanner(string somethingToSay)
{
Voicer.SaySomething(string.Format("{0}:{1}",
BannerGenerator.GetBanner(), somethingToSay));
}
}
public interface IPlainTalker
{
void SayIt(string somethingToSay);
}
public class TimidSpeaker : IPlainTalker
{
private IConsoleVoicer Voicer { get; set; }
public TimidSpeaker(IConsoleVoicer concoleVoicer)
{
Voicer = concoleVoicer;
}
public void SayIt(string somethingToSay)
{
Voicer.SaySomething(somethingToSay);
}
}
And this is what I've tried:
static void Main(string[] args)
{
var container = new Container();
container.Register<IBannerGenerator, ObnoxiousBannerGenerator>();
container.Register<IPlainTalker, TimidSpeaker>();
container.Register<IBannerTalker, LoudMouth>();
//HERE IS THE DILEMMA! How do I assign
// to IBannerTalker a A LoudMouth contructed with a ConsoleShouter,
// and to IPlainTalkerTalker a A TimidSpeaker contructed with a ConsoleWhisperer
//container.Register<IConsoleVoicer, ConsoleShouter>();
container.Register<IConsoleVoicer, ConsoleWhisperer>();
var bannerTalker = container.GetInstance<IBannerTalker>();
var plainTalker = container.GetInstance<IPlainTalker>();
bannerTalker.SayWithBanner("i am a jerk");
plainTalker.SayIt("people like me");
}
Ric .Net is right in pointing you at the RegisterConditional methods. The following registrations complete your quest:
container.Register<IBannerGenerator, ObnoxiousBannerGenerator>();
container.Register<IPlainTalker, TimidSpeaker>();
container.Register<IBannerTalker, LoudMouth>();
container.RegisterConditional<IConsoleVoicer, ConsoleShouter>(
c => c.Consumer.ImplementationType == typeof(LoudMouth));
container.RegisterConditional<IConsoleVoicer, ConsoleWhisperer>(
c => c.Consumer.ImplementationType == typeof(TimidSpeaker));
I have an interface as below, which I use to add a specific language if it does not exist:
public interface IGetLanguagesService
{
void GetLanguages(ILocalizationService localization);
}
public class LanguageService : IGetLanguagesService
{
ILocalizationService _localizationService;
public void GetLanguages(ILocalizationService localization)
{
_localizationService = localization;
var currentLanguages = _localizationService.GetAllLanguages();
bool exists = false;
foreach (var currentLan in currentLanguages)
{
if (currentLan.IsoCode == "es-ES")
{
exists = true;
}
}
if (!exists)
{
AddLanguage(_localizationService);
}
}
public void AddLanguage(ILocalizationService localization)
{
var languageSE = new Language("es-ES") { CultureName = "es-ES", IsMandatory = true };
localization.Save(languageSE);
}
}
I want to use this at start-up so have created a component composer, which on Initialize() I want to call CallGetLanguages() but Im not entirely sure what should be in Initialize(), I think my DI may be wrong?
public class LanguagesComposer : ComponentComposer<LanguagesComponent>
{
public void Compose(Composition composition)
{
composition.Register<IGetLanguagesService>(Lifetime.Singleton);
composition.Register<ILocalizationService>(Lifetime.Singleton);
composition.Components().Append<LanguagesComponent>();
}
}
public class LanguagesComponent : IComponent
{
public void Initialize()
{
???????
}
public void Terminate()
{
throw new NotImplementedException();
}
IGetLanguagesService _getLanguagesService;
ILocalizationService _localization;
public void CallGetLanguages(IGetLanguagesService getLanguages, ILocalizationService localization)
{
_getLanguagesService = getLanguages;
_localization = localization;
_getLanguagesService.GetLanguages(localization);
}
}
You've passed ILocalizationService localization instance to LanguageService twice, pass it to constructor instead and use a constructor injection. The same issue with LanguagesComponent, pass all its dependencies to constructor instead of methods
While troubleshooting a wcf client issue I came across some code from #marc-gravell here. I read the article a number of times and then decided to try and see if I could use the code for real so I created a console app and pulled it all in.
Wrapper:
public interface IDisposableWrapper<T> : IDisposable
{
T BaseObject { get; }
}
public class DisposableWrapper<T> : IDisposableWrapper<T> where T : class, IDisposable
{
public T BaseObject { get; private set; }
public DisposableWrapper(T baseObject) { BaseObject = baseObject; }
protected virtual void OnDispose()
{
BaseObject.Dispose();
}
public void Dispose()
{
if (BaseObject != null)
{
try
{
OnDispose();
}
catch
{
// swallow...
}
}
BaseObject = null;
}
}
Extensions:
public static class DisposableExtensions
{
// core "just dispose it without barfing"
public static IDisposableWrapper<T> Wrap<T>(this T baseObject)
where T : class, IDisposable
{
if (baseObject is IDisposableWrapper<T>) return (IDisposableWrapper<T>)baseObject;
return new DisposableWrapper<T>(baseObject);
}
// specific handling for service-model
public static IDisposableWrapper<TProxy> Wrap<TProxy, TChannel>(this TProxy proxy)
where TProxy : ClientBase<TChannel>
where TChannel : class
{
return new ClientWrapper<TProxy, TChannel>(proxy);
}
}
ClientWrapper:
public class ClientWrapper<TProxy, TChannel> : DisposableWrapper<TProxy>
where TProxy : ClientBase<TChannel>
where TChannel : class
{
public ClientWrapper(TProxy proxy) : base(proxy)
{
}
protected override void OnDispose()
{
// lots of code per state of BaseObject
//State != CommunicationState.Faulted;
}
}
Now, when I go to use it, I have this:
static void Main(string[] args)
{
using (var proxy = new PLPlacementServiceClient())
{
var result = proxy.GetDocumentClassForNewBusiness();
}
using (var proxy = new PLPlacementServiceClient().Wrap())
{
var result = proxy.BaseObject.GetDocumentClassForNewBusiness();
}
using (var proxy = new PLPlacementServiceClient().Wrap<>())//what goes here?
{
var result = proxy.BaseObject.GetDocumentClassForNewBusiness();
}
}
When I F-12 the PLPlacementServiceClient().Wrap() method , it takes me to the non-generic implementation in the extensions class
IDisposableWrapper<T> Wrap<T>(this T baseObject)
, but I was expecting to be taken to the other signature
IDisposableWrapper<TProxy> Wrap<TProxy, TChannel>(this TProxy proxy)
So here is my question(s), "How do I invoke the ClientBase version of the extension?"
Thank you,
Stephen
You must specify both type parameters for method Wrap. That is:
using (var proxy = new PLPlacementServiceClient().Wrap<PLPlacementServiceClient,/*type of the service contract PLPlacementServiceClient is implementing*/>())
{
var result = proxy.BaseObject.GetDocumentClassForNewBusiness();
}
The design problem is as follows, actual problem consists of 2 modules.
Module 1 classes (External Assembly)
abstract class Letter
{
private int _id;
protected Letter(int id) { _id = id; }
public abstract string Val { get; }
}
class LetterA : Letter
{
public LetterA(int id) : base(id) {}
public override string Val
{
get { return "A"; }
}
}
class WordWithALettersOnly
{
public IList<LetterA> ALetters { get; set; }
}
Module 2 classes
class LetterSmallA : LetterA
{
public LetterSmallA(int id) : base(id) {}
public override string Val
{
get { return "a"; }
}
}
class WordWithSmallALettersOnly : WordWithALettersOnly
{
private IList<LetterSmallA> _aLetters;
public new IList<LetterSmallA> ALetters
{
get { return _aLetters; }
set
{
_aLetters = value;
if(_aLetters != null)
base.ALetters = value.Cast<LetterA>().ToList(); // <-- reference lost
}
}
}
class Program
{
static void Main(string[] args)
{
var smallAWordOnly = new WordwithSmallALettersOnly();
smallAWordOnly.ALetters = new List<LetterSmallA>(){new LetterSmallA(1)};
Console.WriteLine("d : " + smallAWordOnly.ALetters.Count); // --> 1
Console.WriteLine("b : " + ((WordwithALettersOnly)smallAWordOnly).ALetters.Count); // --> 1
smallAWordOnly.ALetters.Add(new LetterSmallA(2)); --> 2
Console.WriteLine("d : " + smallAWordOnly.ALetters.Count);
Console.WriteLine("b : " + ((WordwithALettersOnly)smallAWordOnly).ALetters.Count); // -> 1
}
}
Essentially derived classes are generated in the module 2 and processed in the external assembly module 1, on a/c reference loss.
Is the only way to translate the derived class objects of the module 2 to module 1 class objects
I hope i have been explain clearly the issue, if not i do apologise, would really appreciate solutions to this.
If I understand your question correctly, what you want is to treat IList<LetterSmallA> as IList<LetterA>. This is not possible in C# and for very good reasons: one of the things IList<LetterA> says is possible to do with is is to “try to add any LetterA to it. This is not possible with IList<LetterSmallA> and so there is no built-in way to do what you want.
What you can do is to create your own implementation of IList<T> that wraps another IList<T> of derived type:
class BaseTypeList<TBase, TDerived> : IList<TBase>
where TBase : class
where TDerived : class, TBase
{
private readonly IList<TDerived> m_derivedList;
public BaseTypeList(IList<TDerived> derivedList)
{
m_derivedList = derivedList;
}
public IEnumerator<TBase> GetEnumerator()
{
return m_derivedList.Cast<TBase>().GetEnumerator();
}
public void Add(TBase item)
{
var derivedItem = item as TDerived;
if (derivedItem == null)
throw new ArgumentException();
m_derivedList.Add(derivedItem);
}
public void Clear()
{
m_derivedList.Clear();
}
// other members implemented in a similar fashion
}
(The class constraints are not necessary, but make some code simpler.)
Your setter for ALetters could then look like this:
_aLetters = value;
if(_aLetters == null)
base.ALetters = null;
else
base.ALetters = new BaseTypeList<LetterA, LetterSmallA>(value);