public static class XmlHelper
{
/// <summary>
/// 读取节点值
/// </summary>
/// <param name="Path">XML文件路径</param>
/// <param name="Node1">第一级节点</param>
/// <param name="Node2">第二级节点</param>
/// <returns></returns>
public static string GetXmlReader(string Path, string Node1, string Node2)
{
XmlDocument myDc = new XmlDocument();
myDc.Load(Path);
return myDc.SelectSingleNode(Node1).SelectSingleNode(Node2).InnerText;
}

/// <summary>
/// 创建一个XML文件
/// </summary>
/// <param name="Path">XML文件路径</param>
/// <param name="key">List</param>
/// <param name="value">List</param>
public static void CreateXML(string Path, List<string> key, List<string> value)
{
XmlDocument xmlDoc = new XmlDocument();
XmlNode node = xmlDoc.CreateXmlDeclaration("1.0", "utf-8", "");
xmlDoc.AppendChild(node);
XmlNode root = xmlDoc.CreateElement("Config");
xmlDoc.AppendChild(root);

for (int i = 0; i < key.Count; i++)
{
CreateNode(xmlDoc, root, key[i].ToString(), value[i].ToString());
}
try
{
xmlDoc.Save(Path);
}
catch (Exception e)
{
}
}

/// <summary>
/// 创建一个XML文件中的 节点
/// </summary>
/// <param name="xmlDoc"></param>
/// <param name="parentNode"></param>
/// <param name="name"></param>
/// <param name="value"></param>
public static void CreateNode(XmlDocument xmlDoc, XmlNode parentNode, string name, string value)
{
XmlNode node = xmlDoc.CreateNode(XmlNodeType.Element, name, null);
node.InnerText = value;
parentNode.AppendChild(node);
}

/// <summary>
/// 更新XML中指定节点的值
/// </summary>
/// <param name="Path">XML文件路径</param>
/// <param name="NodeName">需要更改的节点</param>
/// <param name="NodeValue">需要更新的节点值</param>
public static void UpdateNode(string Path, string NodeName, string NodeValue)
{
XmlDocument doc = new XmlDocument();
doc.Load(Path);
XmlNode xn = doc.SelectSingleNode("//" + NodeName + "");
xn.InnerText = NodeValue;
doc.Save(Path);
}

}

转自：https://www.cnblogs.com/allen0118/p/6806305.html