Search DropDownList and Textbox With Sortable Header in Custom Paging In GridView Using MySQL

Hello, I am going to use this article but I don't know how to add the Search which is the dropdownlist and textbox

The data in dropdownlist is ContactName and CompanyName

http://www.aspsnippets.com/Articles/Custom-Paging-in-ASPNet-GridView-using-MySql-Stored-Procedure.aspx

Also I would like to know how to sort the gridview in Header

Thank you so much