Multi-Value parameter Select All

Is there a way to tell if a user has checked Select All for a multi-valued
parameter? I'd like my query to be different if they have.I recall from a previous post that this was not possible.
here is the link to the post.
http://www.microsoft.com/technet/community/newsgroups/dgbrowser/en-us/default.mspx?&query=tell+if+user+selected+all&lang=en&cr=US&guid=&sloc=en-us&dg=microsoft.public.sqlserver.reportingsvcs&p=1&tid=e86a166d-61fa-44d8-867c-fc4f29781b5b&mid=e86a166d-61fa-44d8-867c-fc4f29781b5b
"Michelle" wrote:
> Is there a way to tell if a user has checked Select All for a multi-valued
> parameter? I'd like my query to be different if they have.