如何使用C#解析深度XML值

Question

在Visual Studio 2010,.NET v4中工作

我是C#和XML的新手.使用网站资源,我能够找到一种相当简单的方法来解析特定值的XML.然而,XML变得越来越复杂,我正在使用的方法(通过迭代导航技术)开始看起来相当荒谬,有许多嵌套的reader.Read()调用.我确信这种方式不那么令人尴尬,但是当你拥有的唯一工具就是锤子......

所以,问题是:什么是一个整洁,干净的方式来解析XML(见下文),只有从项目匹配返回所有"动作"值的列表,<item itemkind="Wanted">和<phrase>SomeSearchString</phrase>？

这是XML的一个片段:

<formats>
  <items>
    <item itemkind="NotWanted">
      <phrase>Not this one</phrase>
      <actions>
        <action>
          <actionkind>SetStyle</actionkind>
          <parameter>Normal</parameter>
        </action>
        <action>
          <actionkind>SetMargins</actionkind>
          <parameter>0.25,0.25,1,4</parameter>
        </action>
      </actions>
    </item>

    <item itemkind="Wanted">
      <phrase>SomeSearchString</phrase>
      <actions>
        <action>
          <actionkind>Action 1</actionkind>
          <parameter>Param 1</parameter>
        </action>
        <action>
          <actionkind>Action 2</actionkind>
          <parameter>Param 2</parameter>
        </action>
        <action>
          <actionkind>Action 3</actionkind>
          <parameter>Param 3</parameter>
        </action>
      </actions>
    </item>
  </items>

  <styles>
    <style stylename="Normal">
      <fontname>Arial</fontname>
      <fontsize>10</fontsize>
      <bold>0</bold>
    </style>
    <style stylename="Heading">
      <fontname>fntame frhead</fontname>
      <fontsize>12</fontsize>
      <bold>1</bold>
    </style>
  </styles>
</formats>

这是我到达的代码.它确实有效,但是,好吧,看看你自己.请温柔:

public static List<TAction> GetActionsForPhraseItem(string AFileName, string APhrase)
{
   List<TAction> list = new List<TAction>();
   string xmlactionkind = null;
   string xmlparameter = null;
   string match = null;

   // Search through XML items
   using (XmlReader reader = XmlReader.Create(AFileName))
   {
      if (reader.ReadToFollowing("items"))
      {
         while (reader.Read())
         {
            if (reader.ReadToFollowing("item"))
            {
               while (reader.Read())
               {
                  if (reader.NodeType == XmlNodeType.Element && reader.GetAttribute("itemkind") == "Phrase")
                  {
                     if (reader.ReadToFollowing("phrase"))
                     {
                        match = reader.ReadString();
                        if (match == APhrase)
                        {
                           if (reader.ReadToFollowing("actions"))
                           {
                              // Use a subtree to deal with just the aItemKind item actions
                              using (var SubTree = reader.ReadSubtree())
                              {
                                 bool HaveActionKind = false;
                                 bool HaveParameter = false;

                                 while (SubTree.Read())
                                 {
                                    if (SubTree.NodeType == XmlNodeType.Element && SubTree.Name == "actionkind")
                                    {
                                       xmlactionkind = SubTree.ReadString();
                                       HaveActionKind = true;
                                    }

                                    if (SubTree.NodeType == XmlNodeType.Element && SubTree.Name == "parameter")
                                    {
                                       xmlparameter = SubTree.ReadString();
                                       HaveParameter = true;
                                    }

                                    if ((HaveActionKind == true) && (HaveParameter == true))
                                    {
                                       TAction action = new TAction()
                                       {
                                          ActionKind = xmlactionkind,
                                          Parameter = xmlparameter
                                       };

                                       list.Add(action);
                                       HaveActionKind = false;
                                       HaveParameter = false;
                                    }
                                 }
                              }
                           }
                        }
                     }
                  }
               }
            }
         }
      }
   }
   return list;
}

记住我是C#的新手,我怀疑LINQ在这里会非常有用,但到目前为止我还没有能够把它包裹起来.我想,试着一次学习太多新东西.提前感谢任何帮助(和建设性的批评).

编辑:这是我最终的最终工作代码.谢谢大家的回复!

public static List<TAction> GetActionsForPhraseItemTWO(string AFileName, string ASearchPhrase)
{
  List<TAction> list = new List<TAction>();
  var itemKind = "Wanted";
  var searchPhrase = ASearchPhrase;
  var doc = XDocument.Load(AFileName);
  var matches = doc.Descendants("item")
    .Where(x => x.Attribute("itemkind") != null &&
       x.Attribute("itemkind").Value == itemKind &&
       x.Descendants("phrase").FirstOrDefault() != null &&
       x.Descendants("phrase").FirstOrDefault().Value == searchPhrase)
    .SelectMany(x => x.Descendants("action"));
  foreach (var temp in matches)
  {
    TAction action = new TAction()
    {
      ActionKind = temp.Element("actionkind").Value.ToString(),
      Parameter = temp.Element("parameter").Value.ToString()
    };
    list.Add(action);
  }
  return list;
}

Answer 1

Linq to XML 就是您想要的...您还想要操作，对吧？我认为其他任何答案都没有给你这个......

        var itemKind = "Wanted";
        var searchPhrase = "SomeSearchString";
        var doc = XDocument.Load(filename);
        var matches = doc.Descendants("item")
            .Where(x => x.Attribute("itemkind") != null &&
                x.Attribute("itemkind").Value == itemKind &&
                x.Descendants("phrase").FirstOrDefault() != null &&
                x.Descendants("phrase").FirstOrDefault().Value == searchPhrase)
        .SelectMany(x => x.Descendants("action"));