ASP.Net GridView: Edit only specific columns and not all

hi 

i use these code  for my grid view

http://www.aspsnippets.com/Articles/GridView---Add-Edit-Update-Delete-and-Paging-the-AJAX-way.aspx

here have  Customerid  ,Name  ,Company  column when we click on edit that edit Name and Company Column  .

I want when user click on Edit they can edit just Name column I want they can't edit Company column how i can do it?

best regards