SSIS Expressions Not Working?

I have a SSIS package contai开发者_运维技巧ning an error variable that I would like to email out, but only if it is not blank (no errors). So, I put the constraint @[User::PackageError] != "" between the send email task and the processing tasks. Unfortunately, the email task never happens. I can print out the error variable immediately before this point, and it has all the errors in it, so that's not the problem... Do SSIS expressions not work with strings?

Thanks!

Edit: forgot to mention that if I switch the != to == it doesn't work either, but !isnull will make it work but gives no relevant info.

Ok. Figured out the answer. Even though there is no maximum length for strings, the expression editor cannot handle strings longer than 4000 characters.

The best workaround I have found is to use a script task to check the string. Either have the task return Success or Failure or set an int to be 1 or 0 and use that