Hmm. That would have to be IsEmptyOrIsContainedBy :-}

>Or IsEmptyOrContains to be consistent with current methods.
>
>>I guess you're right. It would me more consistent with other String methods. TBH I don't really like either in that they are not truly descriptive of what the method does :-{
>>
>>Maybe swap it around :

public static bool IsEmptyOrIn(this String str, string longsString)
>>        {
>>            return string.IsNullOrEmpty(str) || longsString.Contains(str);
>>        }
>>       // with
>>      var x = ShortString.IsEmptyOrIn(LongString);

>>