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POPlease help me understand polymorphism when using generics in c#
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Body
I am having a problem understanding how polymorphism works when using generics. As an example, I have defined the following program: <pre><code>public interface IMyInterface { void MyMethod(); } public class MyClass : IMyInterface { public void MyMethod() { } } public class MyContainer<T> where T : IMyInterface { public IList<T> Contents; } </code></pre> I can then do this, which works just fine: <pre><code>MyContainer<MyClass> container = new MyContainer<MyClass>(); container.Contents.Add(new MyClass()); </code></pre> I have many classes that implement MyInterface. I would like to write a method that can accept all MyContainer objects: <pre><code>public void CallAllMethodsInContainer(MyContainer<IMyInterface> container) { foreach (IMyInterface myClass in container.Contents) { myClass.MyMethod(); } } </code></pre> Now, I'd like to call this method. <pre><code>MyContainer<MyClass> container = new MyContainer<MyClass>(); container.Contents.Add(new MyClass()); this.CallAllMethodsInContainer(container); </code></pre> That didn't work. Surely, because MyClass implements IMyInterface, I should be able to just cast it? <pre><code>MyContainer<IMyInterface> newContainer = (MyContainer<IMyInterface>)container; </code></pre> That didn't work either. I can definitely cast a normal MyClass to IMyInterface: <pre><code>MyClass newClass = new MyClass(); IMyInterface myInterface = (IMyInterface)newClass; </code></pre> So, at least I haven't completely misunderstood that. I am unsure exactly how I am to write a method that accepts a generic collection of classes that conform to the same interface. I have a plan to completely hack around this problem if need be, but I would really prefer to do it properly. Thank you in advance.
Tags
<c#><asp.net><generics><asp.net-mvc-2><nested-generics>
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Please help me understand polymorphism when using generics in c#
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