Is this a proper way to use exceptions?

Question

I have a Membership exception which looks like this:

public enum MembershipError
{
    EmailNotFound,
    EmailNotConfirmed,
    IncorrectPassword,
    EmailExists
}

public class MembershipException : ApplicationException
{
    public MembershipError MembershipError { get; set; }

    public MembershipException(MembershipError membershipError)
        : base(Enum.GetName(typeof (MembershipError), membershipError))
    {
        MembershipError = membershipError;
    }
}

Should I use an enum in my exception or make an exception for each enum? Because then I would be putting logic when catching the exception like this:

try
{

}
catch (MembershipException exception)
{
    switch (exception.MembershipError)
    {
        case MembershipError.EmailExists:

            break;
            //etc.
    }
}

My service layer throws these exceptions, the web layer/in the action catches these, generate the proper json and return it to the view. Suggest an alternative please?

JaredPar JaredPar · Accepted Answer · 2011-01-24T18:01:41

Exceptions should only be used for exceptional situations. The errors listed in your enumeration appear to be fairly standard and I would choose not to express them through an exception. Instead I would prefer TryXXX style API over exceptions.

For example

public bool TryGetMembershipData(
  string user, 
  out Data data, 
  out MemberShipError error) {
  ...
}

Is this a proper way to use exceptions?

5 Answers