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POC# Generics Inheritance Problem
 

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    <p>I'd like to add different types of objects derived from one class with generics into a List of base type. I get this compile error</p> <pre><code>Error 2 Argument 1: cannot convert from 'ConsoleApplication1.Stable' to 'ConsoleApplication1.ShelterBase&lt;ConsoleApplication1.AnimalBase&gt;' C:\Users\ysn\Desktop\ConsoleApplication1\ConsoleApplication1\Program.cs 43 26 ConsoleApplication1 </code></pre> <p>I can't see the problem could you provide me an alternative way of doing this kind of thing?</p> <pre><code>abstract class AnimalBase { public int SomeCommonProperty;} abstract class ShelterBase&lt;T&gt; where T : AnimalBase { public abstract List&lt;T&gt; GetAnimals(); public abstract void FeedAnimals(List&lt;T&gt; animals); } class Horse : AnimalBase { } class Stable : ShelterBase&lt;Horse&gt; { public override List&lt;Horse&gt; GetAnimals() { return new List&lt;Horse&gt;(); } public override void FeedAnimals(List&lt;Horse&gt; animals) { // feed them } } class Duck : AnimalBase { } class HenHouse : ShelterBase&lt;Duck&gt; { public override List&lt;Duck&gt; GetAnimals() { return new List&lt;Duck&gt;(); } public override void FeedAnimals(List&lt;Duck&gt; animals) { // feed them } } class Program { static void Main(string[] args) { List&lt;ShelterBase&lt;AnimalBase&gt;&gt; shelters = new List&lt;ShelterBase&lt;AnimalBase&gt;&gt;(); ///////////////////////////// following two lines do not compile shelters.Add(new Stable()); shelters.Add(new HenHouse()); ///////////////////////////// foreach (var shelter in shelters) { var animals = shelter.GetAnimals(); // do sth with 'animals' collection } } } </code></pre>
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    1. COWhat version of .Net are you using ? If it's .Net 4 you need to look into Covariance.
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