The type name 'UserDetailsDataRow' doesn't exist in the type 'UserDetails'

Question

I am new to C# and currently using VS2010. When I try to do this:

UserDetailsTableAdapters.UserDetailsTableAdapter userDetails = new UserDetailsTableAdapters.UserDetailsTableAdapter();
UserDetails.UserDetailsDataTable loginDetailsTable = userDetails.GetData();
UserDetails.UserDetailsDataRow dataRow = null;

I get this error

"The type name 'UserDetailsDataRow' doesn't exist in the type 'UserDetails'"

I have included the using System.Data; Any ideas what might be causing this issue and how to resolve it ?

Edit: UserDetails is a data set. I have a Table Adapter to an Access Database file. What I am trying to accomplish is to go through the set of existing users and at a later stage compare one of the values to check if it already exists. My idea was to get the row and compare one of the columns with a local variable for matches.