Export DataSet to a .csv file

Is there an easy way to export a data set to a csv file or do I have to map each element? I read something like this:

Code:

---

<pnwc:ExportButton
id="btnExcel"
runat="server"
Separator="TAB"
Text="Export to Excel"
FileNameToExport="Books.xls" BackColor="#E0E0E0">
</pnwc:ExportButton>

---

but it tells me that the tag is invalid.

The pnwc prefix indicates that it's a custom third party control which you most likely don't have. You'll need to export your data using your own code.

http://geekswithblogs.net/cubeberg/articles/78814.aspx