求xml修改例子

<user>
<name>a</name>
<pass>1</pass>
</user>
<user>
<name>b</name>
<pass>2</pass>
</user>
如果name=a把pass修改了， 代码怎么写,

给个方法你调用吧

/// <summary>
/// 把数据写到xml文件中
/// </summary>
/// <param name="FileName">要打开的XML文件</param>
/// <param name="ht">Hashtable</param>
/// <param name="IsIndex">是否写到最前面</param>
/// <param name="parentNode">父结点名称</param>
/// <param name="Str">结点内容</param>
public static void WriteXml(string FileName, string parentNode, Hashtable ht, bool IsIndex)
{
//初始化XML文档操作类
XmlDocument myXml = new XmlDocument();

//加载指定的XML文件

try
{
myXml.Load(FileName);
}
catch
{
CreateXml(FileName);
myXml.Load(FileName);
}