Silverlight中使用xml文件（xml文件保存，节点的添加，删除）

我的xml文件

<?xml version="1.0" encoding="utf-8" ?>
<Pushpins>
  <Pushpin>
    <ID>bcab6565-f1c7-4ee3-88a1-ab3115112ca5</ID>
    <Title>nn</Title>
    <Description>mmmm</Description>
    <VELatLongLatitude>37.814344816897488</VELatLongLatitude>
    <VELatLongLongitude>112.31771841645201</VELatLongLongitude>
  </Pushpin>
  <Pushpin>
    <ID>641f277b-da9c-4291-832f-700777a6c9b5</ID>
    <Title>www</Title>
    <Description>wwwww</Description>
    <VELatLongLatitude>34.4796226939071</VELatLongLatitude>
    <VELatLongLongitude>108.88998404145201</VELatLongLongitude>
  </Pushpin>
</Pushpins>