>>>>Hi all,
>>>>
>>>>I need to verify a DataRow has valid values and thus I am checking my PK which is a Guid.
>>>>
>>>>I am doing this:
>>>>

>>>>if ((Guid)dr["Track_Id"] != null || (Guid)dr["Track_Id"] != Guid.Empty)
>>>>{
>>>>
>>>>}
>>>>

>>>>
>>>>I am getting a message "Unreachable expression code detected" on the last portion of the check.
>>>
>>>Second expression would only be evaluated if (Guid)dr["Track_Id"] evaluated to null . I guess you intended &&......
>>
>>Oh, I see the point. I should turn those two around then. Thanks Viv
>>
>>

>>if ((Guid)dr["Track_Id"] != Guid.Empty || (Guid)dr["Track_Id"] != null)
>>

>
>Top of my head I don't think Guid is a nullable type so the second part is probably uneccessary anyway. Maybe:
>

>if (dr["Track_Id"] is Guid && (Guid)dr["Track_Id"] != Guid.Emptyl)

>but that may be overkill ?

Hmm, well I was thinking since the DataRow was derived from a serialized read it could get left null. Paul posted a suggestion for that. You were also right in your first post about && rather than || I just didn't catch it.
Thanks
Tim