Make GetType match typeof base class

Question

I'm writing a role provider to supply user role information to an ASP.NET MVC 4 framework I'm using a library called JDash. The JDash documentation calls for me to write a provider implementing System.Web.Security.RoleProvider , then set its type name in a JDash .config file. So I wrote a stub of my role provider and gave JDash its type name, and JDash found the setting properly and tried to instantiate my RoleProvider . However, it kept failing with:

"Custom role provider must implement System.Web.Security.RoleProvider abstract class"

Even though I was absolutely sure that my class was implementing RoleProvider properly.

So I took a look at the JDash source code and found how it's checking that the set role provider implements RoleProvider :

Type type = Type.GetType(config["roleProvider"]);
if (!(type == typeof (RoleProvider)))
      throw new ArgumentException("Custom role provider must implement System.Web.Security.RoleProvider abstract class");

The problem is, GetType() returns the actual runtime type of my role provider...which is not System.Web.Security.RoleProvider , it's a class derived from System.Web.Security.RoleProvider , so of course it doesn't match typeof(RoleProvider) . My class and RoleProvider are of different types; one just happens to be derived from the other, a fact that typeof happily ignores. So if I'm looking at this right, JDash has a bug that makes it impossible to give it a role provider that returns its runtime type as something other than RoleProvider.

I'll be reporting this bug and hoping for a fix, but for the time being, is there some way I can work around it? Could I somehow make GetType("MyRoleProviderDerivedClass") return the type of RoleProvider ? Or can I trick typeof somehow, so that it thinks MyRoleProviderDerivedClass is the same as the RoleProvider base class?

Answer 1

There is no way around this because you can't hook into the comparison or into typeof . This is a simple reference comparison.