Question

Is there a way for a custom assembly to rename and exposes a type from the 3rd party dll?

// Assembly Foo (cannot change code)
namespace Foo
{
    enum XValues
    {
        Val1, Val2;
    }
}

// Assembly Bar
// References Foo
namespace Bar
{
    using Foo;
    // Code that exposes Foo.XValues as Bar.YValues
}

// Assembly Client
// References Bar
namespace Client
{
    void Main() {
        Console.WriteLine(Bar.YValues.Val1);
    }
}

Answer 1

Is there a way for a custom assembly to rename and exposes a type from the 3rd party dll?

No, is the short answer. A type is a type is a type. You could create your own enum in Bar which has the same values, and convert between them where you need to.

What are you trying to achieve – what’s the bigger picture? There may well be a better solution than the one you’re thinking of.