Getting type arguments of generic interfaces that a class implements

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();