c# - 从 LINQ 和 C# 中的 XML 文件中检索节点值

Question

我有一个 xml 文件，我想将message属性中的值从string以下结构中检索到数组中：

<Exceptions>
  <Exception Name="Address">
    <Error id="Line1" message="Address Line 1 is required"/>
    <Error id="Line1Length" message="Address Line 1 must be in-between 1 and 50"/>
    <Error id="Line2Length" message="Address Line 2 must be in-between 1 and 50"/>
  </Exception>
  <Exception Name="Email">
    <Error id="Line1" message="Email is required"/>
  </Exception>
</Exceptions>

如何使用 LINQ-XML 做到这一点？

Answer 1

string id = "Line1Length";
XDocument xdoc = XDocument.Load(path_to_xml);
var messages = xdoc.Descendants("Error")
                   .Where(e => (string)e.Attribute("id") == id)
                   .Select(e => (string)e.Attribute("message"));

此外，如果您没有提供 xml 文件的完整结构，则：

var messages = xdoc.Descendants("Exceptions")
                   .Element("Exception")
                   .Elements("Error")
                   .Where(e => (string)e.Attribute("id") == id)
                   .Select(e => (string)e.Attribute("message"));

顺便说一句，这将返回IEnumerable<string> messages。如果你想要数组，那么ToArray()在选择运算符之后应用。

Answer 2

像这样的东西：

string xml = "<Exceptions>
  <Exception Name='Address'>
    <Error id='Line1' message='Address Line 1 is required'/>
    <Error id='Line1Length' message='Address Line 1 must be in-between 1 and 50'/>
    <Error id='Line2Length' message='Address Line 2 must be in-between 1 and 50'/>
  </Exception>
</Exceptions>";

var document = XDocument.Load(new XmlTextReader(xml));
var messages = document.Descendants("Error").Attributes("message").Select(a => a.Value);