Showing role of user on UsersDisp.aspx


I wanted to show the Role column of user on UsersDisp.aspx so that i can filter the users. I added the role column on page but now have no idea where to get the user's role from database or SharePoint user list.
Can anyone please guide me how to show role's column.
You'll have to modify the data source for the data to include the roles: FBAUserView.cs

It's a combination of data from SharePoint and the membership database.