Add a hyperlinked column to gridview

I am using an excel spreadsheet as a datasource for showing keyword search results from the spreadsheet in a gridview. The spreadsheet has 4 columns: MP Number, Revision Date, MFG, and Description. I am able to show all the 4 columns along with the search feature.

I now need to add an additional column showing a pdf logo for each row in the gridview. On clicking the pdf logo, the user must show up a pdf document pertaining to that MP number.

The excel spreadsheet is in the App_Data folder. The pdf documents are on a different server.

 Here's my code:

<ajax:UpdatePanel ID="Results" runat="se ...