读写xml文件的2个小函数

#region 读写xml文件的2个小函数，2005 4 2 by hyc
    public void SetXmlFileValue(string xmlPath,string AppKey,string AppValue)//写xmlPath是文件路径+文件名，AppKey是 Key Name，AppValue是Value
    {
     XmlDocument xDoc = new XmlDocument();
     xDoc.Load(xmlPath);
     XmlNode xNode;
     XmlElement xElem1;
     XmlElement xElem2;
     xNode =  xDoc.SelectSingleNode("//appSettings");
     xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@key='" + AppKey + "']");
     if ( xElem1 != null )
     {
    xElem1.SetAttribute("value",AppValue);
     }
     else
     {
    xElem2 = xDoc.CreateElement("add");
    xElem2.SetAttribute("key",AppKey);
    xElem2.SetAttribute("value",AppValue);
    xNode.AppendChild(xElem2);
     }
     xDoc.Save(xmlPath);
    }
    public void GetXmlFileValue(string xmlPath,string AppKey,ref string AppValue)//读xmlPath是文件路径+文件名，AppKey是 Key Name，AppValue是Value
    {
     XmlDocument xDoc = new XmlDocument();