Getting type arguments of generic interfaces that a class implements

Question

I have a generic interface, say IGeneric. For a given type, I want to find the generic arguments which a class imlements via IGeneric.

It is more clear in this example:

Class MyClass : IGeneric<Employee>, IGeneric<Company>, IDontWantThis<EvilType> { ... }  Type t = typeof(MyClass); Type[] typeArgs = GetTypeArgsOfInterfacesOf(t);  // At this point, typeArgs must be equal to { typeof(Employee), typeof(Company) } 

What is the implementation of GetTypeArgsOfInterfacesOf(Type t)?

Note: It may be assumed that GetTypeArgsOfInterfacesOf method is written specifically for IGeneric.

Edit: Please note that I am specifically asking how to filter out IGeneric interface from all the interfaces that MyClass implements.

Related: Finding out if a type implements a generic interface

Answer 1

To limit it to just a specific flavor of generic interface you need to get the generic type definition and compare to the "open" interface (IGeneric<> - note no "T" specified):

List<Type> genTypes = new List<Type>(); foreach(Type intType in t.GetInterfaces()) {     if(intType.IsGenericType && intType.GetGenericTypeDefinition()         == typeof(IGeneric<>)) {         genTypes.Add(intType.GetGenericArguments()[0]);     } } // now look at genTypes 

Or as LINQ query-syntax:

Type[] typeArgs = (     from iType in typeof(MyClass).GetInterfaces()     where iType.IsGenericType       && iType.GetGenericTypeDefinition() == typeof(IGeneric<>)     select iType.GetGenericArguments()[0]).ToArray();