Help Passing UserName To The WHEREclause Using The Configure DataSource Wizzard In Visual Studio UI

 (I asked this question in another forum, but think it may be more of  asql question)

Hi.
I bet this is a 101 question, but i'd appreciate any help!
I am in the 'where...' section of the configure data source wizzard .(Visual Studio 2005)
 
Column:(From my table) I select 'UserName' from drop-down
Operator: I select '=' from drop-down
BUT how do I get the UserName (The user is signed into the app)  to pass to the where clause?

Is it from the Form? Profile? Session?
Ive tried         Form.Page.User.Identity.Name.ToString;
                    Form.NamingContainer.Page.User.Identity.Name.ToString;
                    Profile.UserName;
 
NOTHING works. IF I set the default value to a user name (eg joe_user) it retrieves fine, but I need it to retrieve for the currently signed in user.
 
THANKS In advance....
 
Dan