获取root节点ID

Question

这里是我的XML结构：

<DirectoryNode Id="297fe1ac-ff9b-4c40-ada4-86dc713a9537" Title="Root"> 
    <DirectoryNode Id="80e01248-1170-4393-a327-b97409d51159" Title="A"> 
     <DirectoryNode Id="e6db6d3f-be30-4cdf-b79e-864cc9b52c5f" Title="A1"> 
     <DirectoryNode Id="4368d898-6fb0-4e2f-ba56-edbaf4bd0077" Title="A11" /> 
     </DirectoryNode> 
     <DirectoryNode Id="11c5336b-462e-45dc-b4d3-92032ebc3ae3" Title="A2" /> 
    </DirectoryNode> 
    <DirectoryNode Id="b983fd39-fc2e-43e0-80e6-3808fb47f995" Title="B"> 
     <DirectoryNode Id="433851d6-9935-4adb-9acb-7055c26e85cb" Title="B1"> 
     <DirectoryNode Id="f2602aed-6d97-4e46-9e8a-fb181b28f0c8" Title="B11" /> 
     </DirectoryNode> 
    </DirectoryNode> 
    <DirectoryNode Id="9144d8cf-93c0-4de6-9109-448d396a9e17" Title="C" /> 
    <DirectoryNode Id="182491af-452e-40bc-b51e-59f078db3ad3" Title="D" /> 
</DirectoryNode> 

我想要做的就是根节点（而不是主根节点）ID给予目录节点ID。下面是一些例子：

1. 鉴于A11的ID，我要的ID
2. 由于A2的ID，我要的ID
3. 给出的ID，我要的ID
4. 鉴于B1的ID，我想B的Id

我很可怕，当谈到解析XML和拉出值 - 有没有人知道一个快速的方法来做到这一点？

Answer 1

听起来像是你可以使用类似：

XDocument doc = XDocument.Parse("nodes.xml"); 
XElement node = doc.Descendants("DirectoryNode") 
        .Where(n => (string) n.Attribute("Id") == id) 
        .Single(); 

// Now go up until we find the highest node beneatht the document root node 
while (node.Parent != doc.Root) 
{ 
    node = node.Parent; 
} 

注意，如果可以有多个节点使用相同的ID，或者ID可能不会出现在所有的，你必须改变你的查询。例如，如果你只关心第一场比赛，但有可能是不匹配的，你可以改变Single到FirstOrDefault()，然后（在while循环之前）使用方法：

if (node == null) 
{ 
    // No matches. Take appropriate action here. 
} 

Answer 2

这里是做的有点递归的方式它。

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

namespace Test 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      string sampleXml = @"<DirectoryNode Id=""297fe1ac-ff9b-4c40-ada4-86dc713a9537"" Title=""Root"">" + Environment.NewLine + 
           @" <DirectoryNode Id=""80e01248-1170-4393-a327-b97409d51159"" Title=""A"">" + Environment.NewLine + 
           @"  <DirectoryNode Id=""e6db6d3f-be30-4cdf-b79e-864cc9b52c5f"" Title=""A1"">" + Environment.NewLine + 
           @"   <DirectoryNode Id=""4368d898-6fb0-4e2f-ba56-edbaf4bd0077"" Title=""A11"" />" + Environment.NewLine + 
           @"  </DirectoryNode>" + Environment.NewLine + 
           @"  <DirectoryNode Id=""11c5336b-462e-45dc-b4d3-92032ebc3ae3"" Title=""A2"" />" + Environment.NewLine + 
           @" </DirectoryNode>" + Environment.NewLine + 
           @" <DirectoryNode Id=""b983fd39-fc2e-43e0-80e6-3808fb47f995"" Title=""B"">" + Environment.NewLine + 
           @"  <DirectoryNode Id=""433851d6-9935-4adb-9acb-7055c26e85cb"" Title=""B1"">" + Environment.NewLine + 
           @"   <DirectoryNode Id=""f2602aed-6d97-4e46-9e8a-fb181b28f0c8"" Title=""B11"" />" + Environment.NewLine + 
           @"  </DirectoryNode>" + Environment.NewLine + 
           @" </DirectoryNode>" + Environment.NewLine + 
           @" <DirectoryNode Id=""9144d8cf-93c0-4de6-9109-448d396a9e17"" Title=""C"" />" + Environment.NewLine + 
           @" <DirectoryNode Id=""182491af-452e-40bc-b51e-59f078db3ad3"" Title=""D"" />" + Environment.NewLine + 
           @"</DirectoryNode>" + Environment.NewLine + 
           @""; 

      XDocument document = XDocument.Parse(sampleXml); 

      // Given A11's Id, I want A's Id 
      XElement parentDirectory = GetParentDirectory(document.Descendants("DirectoryNode").Single(element => (string) element.Attribute("Title") == "A11")); 
      Console.WriteLine(parentDirectory.Attribute("Title").Value); 

      // Given A2's Id, I want A's Id 
      parentDirectory = GetParentDirectory(document.Descendants("DirectoryNode").Single(element => (string)element.Attribute("Title") == "A2")); 
      Console.WriteLine(parentDirectory.Attribute("Title").Value); 

      // Given A's Id, I want A's Id 
      parentDirectory = GetParentDirectory(document.Descendants("DirectoryNode").Single(element => (string)element.Attribute("Title") == "A")); 
      Console.WriteLine(parentDirectory.Attribute("Title").Value); 

      // Given B1's Id, I want B's Id 
      parentDirectory = GetParentDirectory(document.Descendants("DirectoryNode").Single(element => (string)element.Attribute("Title") == "B1")); 
      Console.WriteLine(parentDirectory.Attribute("Title").Value); 

      Console.ReadLine(); 
     } 

     public static XElement GetParentDirectory(XElement element) 
     { 
      if (element.Parent == element.Document.Root) 
       return element; 

      return GetParentDirectory(element.Parent); 
     } 
    } 
}