it is some thing like this, in your code behind, after you have reference the DLL's to a new application, you can type this to know what functions can be override.

using NamespaceFromDLL //this namespace is namespace use by the DLL that you want to override

public class SomeClass
{
     public override .....//in this area, it will automatically show all functions/methods that you can
                           //override, if nothing shows, if means there area no functions/methods that
                           //are declared as virtual.
}

Please mark as an Answer if this helps you, thnxs