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    <p>I use the following to create and init some of the classes that need default and shared behaviour. Maybe if you can refactor it will help:</p> <p>It is some form of the <a href="http://en.wikipedia.org/wiki/Factory_method_pattern" rel="nofollow">Factory</a> and <a href="http://en.wikipedia.org/wiki/Flyweight_pattern" rel="nofollow">FlyWeight</a> patterns combined (the flyweight part can be removed in your scenario), which in addition has a concept of class Type shared handlers.</p> <p>I simplified and removed some stuff that you wont need but there is more to remove, I added comments.</p> <p>Usage would be: (app init)</p> <pre><code>Dictionary&lt;int,int&gt; vacationWeeksTable = new Dictionary&lt;int,int&gt;(); // fill the table Factory&lt;Employee&gt;.Init(vacationWeeksTable); </code></pre> <p>The whenever you create a Employee class:</p> <pre><code>// remove grouping in the factory class to remove this null Employee em = Factory&lt;Employee&gt;.Create(null); </code></pre> <p>It takes only a WeakReference to the classes so you don't have to worry about GC.</p> <p>Each employee will have the shared vacationWeeksTable setup on creation, without the possibility to change it after from outside if not using the factory class.</p> <p>You could change the vacation table for all running instances of Employee at any moment in the runtime of the app with:</p> <pre><code>// this will call the method registered for SetInitialdata on all instances of Employee classes. // again remove grouping to remove that null Factory&lt;Employee&gt;.Call(EventHandlerTypes.SetInitialData, null, vacTable); </code></pre> <p>Sample implementation of Employee:</p> <pre><code>class Employee : IBaseClass { private Dictionary&lt;int, int&gt; vacationWeeksTable; public virtual void RegisterSharedHandlers(int? group, Action&lt;IKey, int?, EventHandlerTypes, Action&lt;object, SharedEventArgs&gt;&gt; register) { group = 0; // disable different groups register(new Key&lt;Employee, int&gt;(0), group, EventHandlerTypes.SetInitialData, SetVacationWeeksTable); } public virtual void RegisterSharedData(Action&lt;IKey, object&gt; regData) { // remove this from factory and interface, you probably dont need it // I have been using it as a FlyWeight data store for classes. } private void SetVacationWeeksTable(object sender, SharedEventArgs e) { vacationWeeksTable = e.GetData&lt;Dictionary&lt;int, int&gt;&gt;(); } } </code></pre> <p><strong>Code pattern Implementation:</strong></p> <p>IBaseClass : interface that each of my classes that are creatable through a factory implement</p> <pre><code>public enum EventHandlerTypes { SetInitialData // you can add additional shared handlers here and Factory&lt;C&gt;.Call - it. } public class SharedEventArgs : EventArgs { private object data; public SharedEventArgs(object data) { this.data = data; } public T GetData&lt;T&gt;() { return (T)data; } } public interface IBaseClass { void RegisterSharedHandlers(int? group, Action&lt;IKey, int?, EventHandlerTypes, Action&lt;object, SharedEventArgs&gt;&gt; regEvent); void RegisterSharedData(Action&lt;IKey, object&gt; regData); } </code></pre> <p>Utility generic classes:</p> <pre><code>public interface IKey { Type GetKeyType(); V GetValue&lt;V&gt;(); } public class Key&lt;T, V&gt; : IKey { public V ID { get; set; } public Key(V id) { ID = id; } public Type GetKeyType() { return typeof(T); } public Tp GetValue&lt;Tp&gt;() { return (Tp)(object)ID; } } public class Triple&lt;T, V, Z&gt; { public T First { get; set; } public V Second { get; set; } public Z Third { get; set; } public Triple(T first, V second, Z third) { First = first; Second = second; Third = third; } } </code></pre> <p>Factory class with slight modification to handle your scenario:</p> <pre><code> public static class Factory&lt;C&gt; where C : IBaseClass, new() { private static object initialData; private static Dictionary&lt;IKey, Triple&lt;EventHandlerTypes, int, WeakReference&gt;&gt; handlers = new Dictionary&lt;IKey, Triple&lt;EventHandlerTypes, int, WeakReference&gt;&gt;(); private static Dictionary&lt;IKey, object&gt; data = new Dictionary&lt;IKey, object&gt;(); static Factory() { C newClass = new C(); newClass.RegisterSharedData(registerSharedData); } public static void Init&lt;IT&gt;(IT initData) { initialData = initData; } public static Dt[] GetData&lt;Dt&gt;() { var dataList = from d in data where d.Key.GetKeyType() == typeof(Dt) select d.Value; return dataList.Cast&lt;Dt&gt;().ToArray(); } private static void registerSharedData(IKey key, object value) { data.Add(key, value); } public static C Create(int? group) { C newClass = new C(); newClass.RegisterSharedHandlers(group, registerSharedHandlers); // this is a bit bad here since it will call it on all instances // it would be better if you can call this from outside after creating all the classes Factory&lt;C&gt;.Call(EventHandlerTypes.SetInitialData, null, initialData); return newClass; } private static void registerSharedHandlers(IKey subscriber, int? group, EventHandlerTypes type, Action&lt;object, SharedEventArgs&gt; handler) { handlers.Add(subscriber, new Triple&lt;EventHandlerTypes, int, WeakReference&gt;(type, group ?? -1, new WeakReference(handler))); } public static void Call&lt;N&gt;(EventHandlerTypes type, int? group, N data) { Call&lt;N&gt;(null, type, group, data); } public static void Call&lt;N&gt;(object sender, EventHandlerTypes type, int? group, N data) { lock (handlers) { var invalid = from h in handlers where h.Value.Third.Target == null select h.Key; // delete expired references foreach (var inv in invalid.ToList()) handlers.Remove(inv); var events = from h in handlers where h.Value.First == type &amp;&amp; (!@group.HasValue || h.Value.Second == (int)@group) select h.Value.Third; foreach (var ev in events.ToList()) { // call the handler ((Action&lt;object, SharedEventArgs&gt;)ev.Target)(sender, arg); } } } } </code></pre>
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    1. COThis is most helpful! Thanks, accepted.
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    2. COI added a lock on the Call method, please update your code to be thread safer :) i did not use threads so I did not bother but it should not be posted like that to use :)
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