/// <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
  //========================================================= //
}