Retrieve all fields values from SQLDataSource selected in bound DropDownList

Hello all
I have a drop down list bounded to a sqldatasource. 
After a user selected an item in drop down list, i want to use other fields of the selected row to display or using for filtering another sqldata source, how i can access the selected row of the sqlDatasource.
I appreciate for help
here is the code example.
The sqldatasource return 9 fields, filtered on Email, then the drop down list return value MusicSerial which i use to work latter, 
but i need to access "StudentSerial" or even other fields to work latter.
For example how i can display FN in a label inside form?
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:dtcProjects %>" SelectCommand="SELECT [StudentSerial], [MusicSerial], [FN], [LN], [Email], [TitleEN], [TitleFA], [DetailEN], [DetailFA] FROM [viewStudent ...