Asp.net 2005: Generate CSV file and popup

//prepare the output stream
Response.Clear();
Response.ContentType = "text/csv";
Response.AppendHeader("Content-Disposition",string.Format("attachment; filename={0}", fileName));

//write the csv column headers
DataTable dt1;
dt1 = ds.Tables[1];
foreach (DataRow row in dt1.Rows)
{
for (int i = 0; i < dt1.Columns.Count; i++)
{
Response.Write("\"" + row[i].ToString() + "\"");
Response.Write((i < dt1.Columns.Count - 1) ? delimiter : Environment.NewLine);
}
}
DataTable dt;
dt = ds.Tables[0];
//write the data
foreach (DataRow row in dt.Rows)
{
for (int i = 0; i < dt.Columns.Count; i++)
{
Response.Write("\"" + row[i].ToString() + "\"" );
Response.Write((i < dt.Columns.Count - 1) ? delimiter : Environment.NewLine);
}
}

Response.End();