The issue is that the XmlDataSource control has caching enabled by default, which is why you always see the same row getting bound (unless you rebuild the app or restart the web server). Just modify the XmlDataSource code as follows, and it will work (new code in bold):

XmlDataSource dataSource = new XmlDataSource();
            dataSource.EnableCaching = false;
            dataSource.Data = xmlStrList[i];

Regards,

Andrew