XML文件读取工具类

/// <summary>
/// Author: jiangxiaoqiang
/// </summary>
public class XmlReader
{
    //========================================================= //

    #region 获取XmlDocument对象

    /// <summary>
    /// 根据XML文件内容获取XmlDocument对象
    /// </summary>
    /// <param name="xmlFileContent"></param>
    /// <returns></returns>
    public static XmlDocument GetXmlDocByXmlContent(string xmlFileContent)
    {
        if (string.IsNullOrEmpty(xmlFileContent))
        {
            return null;
        }

        var xDoc = new XmlDocument();
        try
        {
            xDoc.LoadXml(xmlFileContent);
        }
        catch
        {
            xDoc = null;
        }

        return xDoc;
    }

    /// <summary>
    /// 根据XML文件路径获取XmlDocument对象
    /// </summary>
    /// <param name="xmlFilePath"></param>
    /// <returns></returns>
    public static XmlDocument GetXmlDocByFilePath(string xmlFilePath)
    {
        if (string.IsNullOrEmpty(xmlFilePath) || !File.Exists(xmlFilePath))
        {
            return null;
        }

        var xDoc = new XmlDocument();
        try
        {
            xDoc.Load(xmlFilePath);
        }
        catch
        {
            throw new Exception(string.Format("请确认该XML文件格式正确，路径为：{0}", xmlFilePath));
        }

        return xDoc;
    }

    #endregion

    //========================================================= //


    //========================================================= //

    #region 获取XML节点（或节点列表）

    /// <summary>
    /// 获取父节点下指定节点名称的第一个子节点
    /// </summary>
    /// <param name="parentXmlNode"></param>
    /// <param name="childNodeName"></param>
    /// <returns></returns>
    public static XmlNode GetFirstChildNodeByName(XmlNode parentXmlNode, string childNodeName)
    {
        var childXmlNodes = GetChildNodesByName(parentXmlNode, childNodeName);
        if (childXmlNodes != null && childXmlNodes.Count > 0)
        {
            return childXmlNodes[0];
        }

        return null;
    }

    /// <summary>
    /// 获取父节点下指定节点名称的子节点列表
    /// </summary>
    /// <param name="parentXmlNode">父节点</param>
    /// <param name="nodeName">节点名称</param>
    /// <returns></returns>
    public static XmlNodeList GetChildNodesByName(XmlNode parentXmlNode, string nodeName)
    {
        if (parentXmlNode == null || string.IsNullOrEmpty(nodeName))
        {
            return null;
        }

        return GetChildNodesByXPathExpr(parentXmlNode, string.Format(".//{0}", nodeName));
    }

    /// <summary>
    /// 获取父节点下满足xpathExpr表达式的XML子节点列表
    /// </summary>
    /// <param name="parentXmlNode">父节点</param>
    /// <param name="xpathExpr"></param>
    /// <returns></returns>   
    public static XmlNodeList GetChildNodesByXPathExpr(XmlNode parentXmlNode, string xpathExpr)
    {
        if (parentXmlNode == null || string.IsNullOrEmpty(xpathExpr))
        {
            return null;
        }

        return parentXmlNode.SelectNodes(xpathExpr);
    }

    /// <summary>
    /// 获取父节点下的第一个子节点
    /// </summary>
    /// <param name="parentXmlNode"></param>
    /// <returns></returns>
    public static XmlNode GetFirstChildNode(XmlNode parentXmlNode)
    {
        var childXmlNodes = GetChildNodes(parentXmlNode);
        if (childXmlNodes != null && childXmlNodes.Count > 0)
        {
            return childXmlNodes[0];
        }

        return null;
    }

    /// <summary>
    /// 获取父节点的子节点列表
    /// </summary>
    /// <param name="parentXmlNode">父节点</param>
    /// <returns></returns>
    public static XmlNodeList GetChildNodes(XmlNode parentXmlNode)
    {
        return parentXmlNode == null ? null : parentXmlNode.ChildNodes;
    }

    #endregion
    //========================================================= //


    //========================================================= //

    #region 读取节点属性值

    /// <summary>
    /// 读取某个XML节点的属性值（根据属性名）
    /// </summary>
    /// <param name="xmlNode"></param>
    /// <param name="attrName"></param>
    /// <returns></returns>
    public static string ReadAttrValue(XmlNode xmlNode, string attrName)
    {
        var xmlElement = xmlNode as XmlElement;

        return xmlElement == null ? null : xmlElement.GetAttribute(attrName);
    }

    /// <summary>
    /// 读取父节点下指定节点名和属性名的第一个子节点的属性值
    /// </summary>
    /// <param name="parentXmlNode">XML父节点</param>
    /// <param name="childNodeName">节点名称</param>
    /// <param name="attrName">属性名</param>
    /// <returns></returns>
    public static string ReadFirstAttrValue(XmlNode parentXmlNode, string childNodeName, string attrName)
    {
        var attrVals = ReadAttrValues(parentXmlNode, childNodeName, attrName);
        return (attrVals == null || attrVals.Length == 0) ? null : attrVals[0];
    }

    /// <summary>
    /// 读取父节点下指定节点名和属性名的所有子节点的该属性值的数组
    /// </summary>
    /// <param name="parentXmlNode">XML文档</param>
    /// <param name="childNodeName">节点名称</param>
    /// <param name="attrName">属性名</param>
    /// <returns></returns>
    public static string[] ReadAttrValues(XmlNode parentXmlNode, string childNodeName, string attrName)
    {
        if (parentXmlNode == null || string.IsNullOrEmpty(childNodeName) || string.IsNullOrEmpty(attrName))
        {
            return null;
        }

        var xpathExpr = string.Format("//{0}[@{1}]", childNodeName, attrName);
        var nodes = GetChildNodesByXPathExpr(parentXmlNode, xpathExpr);
        if (nodes != null && nodes.Count > 0)
        {
            var nodeCount = nodes.Count;
            var attrVals = new string[nodeCount];
            for (var i = 0; i < nodeCount; i++)
            {
                attrVals[i] = ((XmlElement)nodes[i]).GetAttribute(attrName);
            }

            return attrVals;
        }

        return null;
    }

    #endregion

    //========================================================= //


    //========================================================= //

    #region 读取父节点下的子节点的文本内容

    /// <summary>
    /// 读取父节点下指定节点名的第一个子节点的文本
    /// </summary>
    /// <param name="parentXmlNode"></param>
    /// <param name="childNodeName"></param>
    /// <returns></returns>
    public static string ReadFirstChildNodeTextByName(XmlNode parentXmlNode, string childNodeName)
    {
        var childNodeTexts = ReadChildNodeTextsByName(parentXmlNode, childNodeName);
        if (childNodeTexts != null && childNodeTexts.Length > 0)
        {
            return childNodeTexts[0];
        }

        return null;
    }

    /// <summary>
    /// 读取父节点下指定节点名的所有子节点的文本数组
    /// </summary>
    /// <param name="parentXmlNode"></param>
    /// <param name="childNodeName"></param>
    /// <returns></returns>
    public static string[] ReadChildNodeTextsByName(XmlNode parentXmlNode, string childNodeName)
    {
        if (parentXmlNode == null || string.IsNullOrEmpty(childNodeName))
        {
            return null;
        }

        var xpathExpr = string.Format(".//{0}", childNodeName);
        var childNodes = GetChildNodesByXPathExpr(parentXmlNode, xpathExpr);
        if (childNodes != null && childNodes.Count > 0)
        {
            var nodeCount = childNodes.Count;
            var nodeTexts = new string[nodeCount];
            for (var i = 0; i < nodeCount; i++)
            {
                nodeTexts[i] = childNodes[i].InnerText;
            }

            return nodeTexts;
        }

        return null;
    }

    /// <summary>
    /// 读取父节点下的第一个子节点的文本
    /// </summary>
    /// <param name="parentXmlNode"></param>
    /// <returns></returns>
    public static string ReadFirstChildNodeText(XmlNode parentXmlNode)
    {
        var childNodeTexts = ReadChildNodeTexts(parentXmlNode);
        if (childNodeTexts != null && childNodeTexts.Length > 0)
        {
            return childNodeTexts[0];
        }

        return null;
    }

    /// <summary>
    /// 读取父节点下的所有子节点的文本数组
    /// </summary>
    /// <param name="parentXmlNode"></param>
    /// <returns></returns>
    public static string[] ReadChildNodeTexts(XmlNode parentXmlNode)
    {
        if (parentXmlNode == null)
        {
            return null;
        }

        var childNodes = GetChildNodes(parentXmlNode);
        if (childNodes != null && childNodes.Count > 0)
        {
            var nodeCount = childNodes.Count;
            var nodeTexts = new string[nodeCount];
            for (var i = 0; i < nodeCount; i++)
            {
                nodeTexts[i] = childNodes[i].InnerText;
            }

            return nodeTexts;
        }

        return null;
    }

    /// <summary>
    /// 读取XML节点文本
    /// </summary>
    /// <param name="xmlNode"></param>
    /// <returns></returns>
    public static string ReadNodeText(XmlNode xmlNode)
    {
        if (xmlNode == null)
        {
            return null;
        }

        return xmlNode.InnerText;
    }

    #endregion

    //========================================================= //
}