Remove Duplicates from Datatable with LINQ without keeping a duplicated entry at all

I have a Datatable with several Columns which I want to remove all duplicates from like that

Dt1 = Dt1 .AsEnumerable().GroupBy(r => new { filename = r.Field<string>("filename1"), filesize = r.Field<string>("filesizeinkb") }).Select(g => g.First()).CopyToDataTable();

However above code leaves one entry (the first one that is found) in the DataTable via the Select.First at the end of the LINQ code.

Is there a way to remove all duplicates and keep none?

Edit:
Example what the code is doing now and what it should do.

Datatable with entries like that

Above LINQ will now remove Line 2 as Filename and Filesize are the same. However Line 1 will stay as the LINQ Code selects the first duplicated entry.

I want to have removed line 1 and line 2 from the Datatable.

>Solution :

Dt1 = Dt1.AsEnumerable()
         .GroupBy(r => new { filename = r.Field<string>("filename1"), filesize = r.Field<string>("filesizeinkb") })
         .Where(g => g.Count() == 1)
         .Select(g => g.First())
         .CopyToDataTable();

That will discard any groups with more than one item, then get the first (and only) item from the rest.