using (SqlConnection conn = new SqlConnection("连接字符串"))//你的连接字符串;
{ //查询出你的新闻,可以按时间排序得到最新的十条;
using (SqlCommand com = new SqlCommand("select top 10 * from [News] order by [提交时间] desc", conn))
{
SqlDataAdapter adapter = new SqlDataAdapter(com);
DataSet ds = new DataSet();
adapter.Fill(ds, "news");
//创建一个xml文件夹,把xml文件放到里面.
ds.Tables["news"].WriteXml(Server.MapPath("xml") + "\\aa.xml");
}
}