Is this redundant code?

Question

I'm upgrading a system and am going through another developers code (ASP.NET in C#).

I came across this:

private ReferralSearchFilterResults ReferralsMatched
{
    get
    {
        if (Session[SESSION_REFERRAL_SEARCHFILTERRESULTS] == null || Session[SESSION_REFERRAL_SEARCHFILTERRESULTS].GetType() != typeof(ReferralSearchFilterResults))
            return null;
        else
            return (ReferralSearchFilterResults)Session[SESSION_REFERRAL_SEARCHFILTERRESULTS];
    }
    set
    {
        if (value == null)
        {
            Session[SESSION_REFERRAL_SEARCHFILTERRESULTS] = value;
        }
        else if (value.GetType() == typeof(ReferralSearchFilterResults))
        {
            Session[SESSION_REFERRAL_SEARCHFILTERRESULTS] = value;
        }
    }

}

Is checking the type on the setter unnecessary? Surely, if I set the property to something other than a ReferralSearchFilterResults object, the code wouldn't even compile? Am I missing something or am I right to think this can be achieved just by using:

set
{
    Session[SESSION_REFERRAL_SEARCHFILTERRESULTS] = value;
}

Answer 1

The original code prevents any subclasses of ReferralSearchFilterResults from being set or get to or from the property. This is because value.GetType() will return the actual Type of the object referenced by value. If that Type is a subclass of ReferralSearchFilterResults, then it will not equals typeof(ReferralSearchFilterResults).

I'm not sure of your context here, so I can't tell you whether that's correct behaviour or not. If it's intended behaviour, it does smell a bit dirty as it will silently ignore any assignments of subclasses. But I can't really judge without more context.

Answer 2

I think you're right - the setter shouldn't compile if provided with something of that cannot be implicitly cast to a ReferralSearchFilterResults.