Need to cast to an object without knowing what type the object is

Question

I am trying to dynamically load my authentication server type based on a setting. I am hung up on how to cast to a type when I don't know the type.

   Type t = Type.GetType(WebConfigurationManager.AppSettings.Get("AuthenticationSvcImpl"));
    IAuthenticationService authCli = Activator.CreateInstance(t);
    return authCli.AuthenticateUser(login);

I know there is Convert.ChangeType(), but that just converts to an object...

Answer 1

var authCli = Activator.CreateInstance(t) as IAuthenticationService;

Answer 2

Is that what you are looking for ?

Type t = Type.GetType(WebConfigurationManager.AppSettings.Get("AuthenticationSvcImpl"));
IAuthenticationService authCli = (IAuthenticationService) Activator.CreateInstance(t);
return authCli.AuthenticateUser(login);