public void SetXmlFileValue(string xmlPath,string AppKey,string AppValue)//寫xmlPath是文件路徑 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)//讀xmlPath是文件路徑 文件名，AppKey是 Key Name，AppValue是Value
{
XmlDocument xDoc = new XmlDocument();
xDoc.Load(xmlPath);
XmlNode xNode;
XmlElement xElem1;

xNode = xDoc.SelectSingleNode("//appSettings");

xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@key='" AppKey "']");
if ( xElem1 != null )
{
AppValue=xElem1.GetAttribute ("value");
}
else
{
// MessageBox.Show ("There is not any information!");
}

}

#endregion