如何合并xml流

Question

我有多个这种格式的 xml 流：

xml1:

<?xml version="1.0" encoding="utf-8"?>
<Node>
      <NodeA>test1</NodeA>
      <NodeB>test2</NodeB>
      <NodeC>
         <Att>test4</Att>
         <Value1>1.0</Value1>
      </NodeC>
</Node>
<Node>
      <NodeA>test1</NodeA>
      <NodeB>test7</NodeB>
      <NodeC>
         <Att>test8</Att>
         <Value1>2.0</Value1>
      </NodeC>
</Node>
...

xmlN:

<?xml version="1.0" encoding="utf-8"?>
<Node>
      <NodeA>test1</NodeA>
      <NodeB>test2</NodeB>
      <NodeC>
         <Att>test4</Att>
         <ValueN>5.0</ValueN>
      </NodeC>
</Node>
<Node>
      <NodeA>test1</NodeA>
      <NodeB>test7</NodeB>
      <NodeC>
         <Att>test8</Att>
         <ValueN>6.0</ValueN>
      </NodeC>
</Node>
<Node>
      <NodeA>test9</NodeA>
      <NodeB>test8</NodeB>
      <NodeC>
         <Att>test8</Att>
         <ValueN>6.0</ValueN>
      </NodeC>
</Node>

我希望合并后的 xml 看起来像这样：

<?xml version="1.0" encoding="utf-8"?>
<Node>
      <NodeA>test1</NodeA>
      <NodeB>test2</NodeB>
      <NodeNEW>test4</Att>
      <Value1>1.0</Value1>
      <ValueN>5.0</ValueN>
</Node>
<Node>
      <NodeA>test1</NodeA>
      <NodeB>test7</NodeB>
      <NodeNEW>test8</NodeNEW>
      <Value1>2.0</Value1>
      <ValueN>6.0</ValueN>
</Node>
<Node>
      <NodeA>test9</NodeA>
      <NodeB>test8</NodeB>
      <NodeNEW>test8</NodeNew>
      <Value1></Value1>
      <ValueN>6.0</ValueN>

</Node>

所以我创建了具有不同 Value1 的唯一键 NodeA>NodeB>NodeNEW，如果此唯一键未出现在其各自的 xml 中，则不会分配任何内容。

最有效的方法是什么？

Answer 1

下面的代码应该会给你想要的结果，如果它没有发布，它不会显示以前节点的值，但你可以玩弄它并让它工作。这里的想法是使用 XMLReader 读取项目并在同一迭代中更新现有节点。

    static void Main(string[] args) {

  //Ideally you should have well formed xml with root element as eg given below
  //but since it is stream it is possible but not sure how much control you have on it.
  //eg: <Nodes><Node1/><Node2/>...</Nodes> 

  //Reading your data from locally stored stream files
  var streamFiles=new[] { @"C:\temp\stack\xml1.xml", @"C:\temp\stack\xmlN.xml" };

  var dict = new Dictionary<int,XElement>();

  foreach(var streamFile in streamFiles) {
    using(var reader=XmlReader.Create(streamFile, new XmlReaderSettings { ConformanceLevel=ConformanceLevel.Fragment })) {
      var nodeNo=0;
      while(reader.MoveToContent()==XmlNodeType.Element) {
        var element=XNode.ReadFrom(reader) as XElement;
        //Now merge the data. Yahoo
        XElement currentElement;
        if(!dict.TryGetValue(nodeNo, out currentElement)) {
          currentElement = new XElement("Node");
          dict.Add(nodeNo, currentElement);
        }

        foreach(var el in element.Elements().Where(e => !e.HasElements)) {
          currentElement.SetElementValue(el.Name, el.Value);
        }

        currentElement.SetElementValue("NodeNEW",
          element.Elements().Where(e => e.HasElements)
            .SelectMany(e => e.Elements()
              .Where(w => w.Name=="Att"))
            .FirstOrDefault().Value);

        currentElement.Add(element.Elements().Where(e => e.HasElements)
          .SelectMany(e => e.Elements()
            .Where(w => w.Name!="Att")));

        nodeNo++;
      }
    }
  }

  using(var writer=XmlWriter.Create(@"C:\temp\stack\xmlMerged.xml",
    new XmlWriterSettings {
      ConformanceLevel=ConformanceLevel.Fragment,
      Indent=true
    })) {
    foreach(var element in dict.Values) {
      element.WriteTo(writer);
    }
  }
}