SSRS Alert/Message box

Hi,

I am using SSRS 2008 R2 according to specification.I need to display alert if the search criteria is not able to retrieve any value.

For Example. I have 2 parameter,

1. Search: Simple textbox. need to enter few character of name

2. Name: Multivalue parameter, It will show list of all name based on search. (Name like @search + %)

Here if Name parameter is not found any value. i want to show message/ Alert box like "Your Search criteria retreived no data".

Thanks in advance

Paramesh G