linq with datatable & dropdown fill by enumerable range

//--- linq example for datatable
 private void CheclLq()
    {
        string str = "select * from login";
        DataUtility dut = new DataUtility();
         _hgfhg = dut.GetDataTable(str);
         var qry=from c in _hgfhg.AsEnumerable() where c.Field<string>("Username")=="ADMIN" select c;
         DataTable x = qry.CopyToDataTable();
         GridView1.DataSource = x;
         GridView1.DataBind();
    }
//------drop down fill by enumetable range


 private void GrpFill()
    {
        var val = Enumerable.Range(18, 10);

        foreach (var item in val)
        {
            DropDownList1.Items.Add(item.ToString());
        }
    }