<BSROOT>
    <BSID>
        <ID>1</ID>
    </BSID>
    <BSID>
        <ID>2</ID>
    </BSID>
    <BSID>
        <ID>3</ID>
    </BSID>

    <ITEM BSID="13064" TMPLNAME="sites" TMPLID="1">
    <BSAC BSTITLE="aaa" BSAV="1" />
    <BSAC BSTITLE="bbb" BSAV="2" />
    <BSAC BSTITLE="ccc" BSAV="3" />
    <BSAC BSTITLE="ddd" BSAV="4" />
  </ITEM>
  <ITEM BSID="13065" TMPLNAME="sites" TMPLID="1">
    <BSAC BSTITLE="aaa" BSAV="5" />
    <BSAC BSTITLE="bbb" BSAV="6" />
    <BSAC BSTITLE="ccc" BSAV="7" />
    <BSAC BSTITLE="ddd" BSAV="8" />
  </ITEM>
  ..............
  </BSROOT>

 Dim st As Integer = (nPage - 1) * cCount
 Dim en As Integer = nPage * cCount
 Dim query As IEnumerable(Of DataRow) = ds.Tables(TableName).AsEnumerable().Where(Function(x) 
                                                                         ds.Tables(TableName).Rows.IndexOf(x) < st Or 
                                                                         ds.Tables(TableName).Rows.IndexOf(x) > en - 1)

        For Each row In query.ToList()
            row.Delete()
        Next