如何使用aspx页面从数据库中写入数据到xml ?

I have some stored proc.s that get data from DB. I made some data access layers classes to get the data from the sql db I have some Xml files that should be filled with this data. I'm supposed to link between them using aspx pages. Now, I want to know how can I read data at the aspx page from the xml file to send it to the server, and how can I write data from the db to the xml files. I have some stored proc.s that get data from DB