FlexMemberShipProvider throws the wrong exception when try to create an account with a duplicate username

[jakejscott]

You are throwing a generic error when trying to register with a duplicate username

throw new MembershipCreateUserException("Cannot register with a duplicate username");

https://github.com/OdeToCode/Memflex/blob/master/src/FlexProviders/Membership/FlexMembershipProvider.cs#L54

I think it should be

throw new MembershipCreateUserException(MembershipCreateStatus.DuplicateUserName);

That way when you map the validation message in the account controller it will say

"User name already exists. Please enter a different user name."

Rather than

"The authentication provider returned an error. Please verify your entry and try again. If the problem persists, please contact your system administrator."

[OdeToCode]

I think a Flex[Something] exception class would work.