How to handle Cross-Site scripting in drop down ?

I am binding drop down and gridview with datatable using framework 2.0.
Drop down : dropdown1.DataSource = datatable1;
Grid View : GridView1.DataSource = datatable1;
While scanning the above code through Fortify Source Code Analysis (SCA) it says vulnerable towards cross-site scripting? Let me know how to handle above issue? I can't set ValidateRequest page property. 
 
...