C#工具类之XmlNode扩展类

using System;
using System.Linq;
using System.Xml;

    /// <summary>
    /// XmlNodeHelper
    /// </summary>
    public static class XmlNodeHelper
    {
        /// <summary>
        /// 获取给定XmlNode所在的Document
        /// </summary>
        /// <param name="parentNode">给定XmlNode</param>
        /// <returns>XmlDocument</returns>
        public static XmlDocument GetDocument(this XmlNode parentNode)
        {
            if (parentNode == null)
            {
                throw new Exception("XmlNode不能为空");
            }

            var document = (parentNode as XmlDocument) ?? parentNode.OwnerDocument;
            if (document == null)
            {
                throw new Exception("XmlDocument不能为空");
            }

            return document;
        }

        /// <summary>
        /// 为给定结点创建子结点
        /// </summary>
        /// <param name="parentNode">给定结点</param>
        /// <param name="name">子结点名称</param>
        /// <returns>子结点</returns>
        public static XmlNode CreateChildNode(this XmlNode parentNode, string name)
        {
            var document = parentNode.GetDocument();
            var node = document.CreateElement(name);
            parentNode.AppendChild(node);

            return node;
        }

        /// <summary>
        /// 为给定结点创建子结点
        /// </summary>
        /// <param name="parentNode">给定结点</param>
        /// <param name="name">子结点名称</param>
        /// <param name="namespaceUri">子结点命名空间</param>
        /// <returns>子结点</returns>
        public static XmlNode CreateChildNode(this XmlNode parentNode, string name, string namespaceUri)
        {
            var document = parentNode.GetDocument();
            var node = document.CreateElement(name, namespaceUri);
            parentNode.AppendChild(node);

            return node;
        }

        /// <summary>
        /// 根据属性名称获取给定结点的属性值
        /// </summary>
        /// <param name="node">给定结点</param>
        /// <param name="attributeName">属性名称</param>
        /// <returns>属性值</returns>
        public static string GetAttribute(this XmlNode node, string attributeName)
        {
            return node.GetAttribute(attributeName, null);
        }

        /// <summary>
        /// 根据属性名称获取给定结点的属性值
        /// </summary>
        /// <param name="node">给定结点</param>
        /// <param name="attributeName">属性名称</param>
        /// <param name="defaultValue">默认值</param>
        /// <returns>属性值</returns>
        public static string GetAttribute(this XmlNode node, string attributeName, string defaultValue)
        {
            if (node.Attributes == null)
            {
                return null;
            }

            var attribute = node.Attributes[attributeName];

            return (attribute != null ? attribute.InnerText : defaultValue);
        }

        /// <summary>
        /// 为给定结点设置属性名称与值(如果不存在属性名称,则新增;否则更改)
        /// </summary>
        /// <param name="node">给定结点</param>
        /// <param name="name">属性名称</param>
        /// <param name="value">属性值</param>
        public static void SetAttribute(this XmlNode node, string name, string value)
        {
            if (node == null || node.Attributes == null)
            {
                return;
            }

            var nodeAttributes = node.Attributes;
            var attribute = nodeAttributes[name, node.NamespaceURI];
            if (attribute == null)
            {
                var document = node.GetDocument();
                attribute = document.CreateAttribute(name, document.NamespaceURI);
                nodeAttributes.Append(attribute);
            }

            attribute.InnerText = value;
        }
    }