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POC# Access to a generic class member whose type is a generic argument type, only via an interface
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  1. POC# Access to a generic class member whose type is a generic argument type, only via an interface
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    copied!<p>I have a generic class who holds a member whose type is an argument type.<br> I want to be able to access this member only by one of the interface it implements.<br> The reason I want to access the member only via this interface, instead of enumerating all the concrete types it could be, is because there are a great number of those types. </p> <p>So concretely I want to find an equivalent of line 61 in that code (it is a compilation error):</p> <pre><code>using System; using System.Linq; /* Interfaces */ public interface IArgumentClass { void IArgumentClassMethod(); } public interface ISpecialArgumentClass { void ISpecialArgumentClassMethod(); } public interface IContainerClass { void IContainerClassClassMethod(); } /* Argument types */ public class ArgumentClass0 : IArgumentClass { public void IArgumentClassMethod(){} } public class SpecialArgumentClass0 : IArgumentClass, ISpecialArgumentClass { public void IArgumentClassMethod(){} public void ISpecialArgumentClassMethod(){} } public class SpecialArgumentClass1 : IArgumentClass, ISpecialArgumentClass { public void IArgumentClassMethod() { } public void ISpecialArgumentClassMethod() { } } /* Container types */ public class GenericContainer&lt;T&gt; : IContainerClass where T : IArgumentClass, new() { public T t = new T(); public void IContainerClassClassMethod() { } } public class NonGenericContainer : IContainerClass { public void IContainerClassClassMethod(){} } /* main program */ public class Test { public static void Main() { // Instantiate IContainerClass[] containers = { new GenericContainer&lt;ArgumentClass0&gt;(), new GenericContainer&lt;SpecialArgumentClass0&gt;(), new GenericContainer&lt;SpecialArgumentClass1&gt;(), new NonGenericContainer() }; // We want to call IContainerClassClassMethod methods on all instances: foreach (IContainerClass container in containers) container.IContainerClassClassMethod(); // We want to call ISpecialArgumentClassMethod on instances where it's possible: foreach (IContainerClass container in containers) { if (container.GetType().IsGenericType &amp;&amp; container.GetType().GetGenericTypeDefinition() == typeof(GenericContainer&lt;&gt;)) { foreach (Type typeArgument in container.GetType().GetGenericArguments()) { if (typeArgument.GetInterfaces().Contains(typeof(ISpecialArgumentClass))) { // Next line is a compilation error. How can I get a similar result? GenericContainer&lt;ISpecialArgumentClass&gt; mySpecializedClassWithSpecialArgument = container as GenericContainer&lt;ISpecialArgumentClass&gt;; mySpecializedClassWithSpecialArgument.t.ISpecialArgumentClassMethod(); } } } } } } </code></pre> <p><em>Note: You can fork and edit the code <a href="http://ideone.com/kUnIqp" rel="nofollow">here</a>.</em></p>
 

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