如何使用Xml属性值获取关联的元素? [英] How can I use an Xml attribute value to get an associated element?

问题描述

我有一个很大的Xml文件，其中包含我的数据.我需要以编程方式从中获取数据.这是一个小得多的文件，但结构完全相同...

I have a large Xml file containing my data. I need to programmatically get data from it. Here is a much smaller file but with the exact same structure ...

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<colours xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Red>
    <Shade id="1">
      <colour>crimson</colour>
    </Shade>
    <Shade id="2">
      <colour>raspberry</colour>
    </Shade>
    <Shade id="3">
      <colour>lava</colour>
    </Shade>
    <Shade id="4">
      <colour>scarlet</colour>
    </Shade>
  </Red>
  <Green>
    <Shade id="1">
      <colour>asparagus</colour>
    </Shade>
    <Shade id="2">
      <colour>emerald</colour>
    </Shade>
    <Shade id="3">
      <colour>lime</colour>
    </Shade>
    <Shade id="4">
      <colour>avocado</colour>
    </Shade>
  </Green>
  <Blue>
    <Shade id="1">
      <colour>cyan</colour>
    </Shade>
    <Shade id="2">
      <colour>sapphire</colour>
    </Shade>
    <Shade id="3">
      <colour>powder</colour>
    </Shade>
    <Shade id="4">
      <colour>iris</colour>
    </Shade>
  </Blue>
</colours>

我需要解决一个单独的阴影，例如知道颜色红色"和阴影ID(例如"3").

I need to resolve an individual shade, knowing the colour e.g. "Red" and the Shade id e.g."3".

以下代码计算了阴影元素的数量，这是我需要的，但是超出此范围的任何内容对我来说仍然是个谜.

The following code counts the number of shade elements, which is something I need but anything beyond this is still a mystery to me.

    string filepath = "C:/Documents/Data.xml";
    XElement MyData = XElement.Load(filepath);

    int count = MyData.Elements("Red")
                         .Elements("shade")
                         .Count();

    Console.Write(count);
    Console.ReadKey();

推荐答案

除了使用XPath谓词外，如其他答案所示，您可以使用LINQ Where()方法为某些条件过滤元素:

Besides using XPath predicate, as demonstrated in the other answer, you can use LINQ Where() method to filter element for certain criteria :

int count = MyData.Elements("Red")
                  .Elements("Shade")
                  .Where(o => (int?)o.Attribute("id") == 3)
                  .Count();

Dotnetfiddle Demo

Dotnetfiddle Demo

_{请注意，XML区分大小写，因此"Shade"不等于"shade"}

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