使用 XElement 查询命名空间中的节点

问题描述

我正在尝试从看起来像这样的 csproj 文件中提取一个节点，但无法让它工作 - 大概是因为命名空间声明.

i'm trying to pull out a node from a csproj file that looks like this, but can't get it to work - presumably because of the namespace declaration.

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" DefaultTargets="Build">
      <PropertyGroup>
          <RegisterForComInterop>true</RegisterForComInterop>

这失败得很惨:

XDocument cpo = XDocument.Load(file);
XmlNamespaceManager nsm = new XmlNamespaceManager(new NameTable());
nsm.AddNamespace("x", "http://schemas.microsoft.com/developer/msbuild/200");
IEnumerable<XElement> list3 = cpo.XPathSelectElements("//x:RegisterForComInterop[.='true']", nsm);

请问大家有什么想法吗?

Anyone any ideas please?

谢谢.

推荐答案

你真的要为此使用 XPath 吗?在 LINQ to XML 中使用命名空间真的很容易:

Do you really want to use XPath for this? It's really easy to use namespaces within LINQ to XML:

XDocument cpo = XDocument.Load(file);
XNamespace x = "http://schemas.microsoft.com/developer/msbuild/2003";
var elements = cpo.Descendants(x + "RegisterForComInterop")
                  .Where(x => (string) x == "true");

或者，如果您绝对确信每个 RegisterForComInterop 都将具有适当的布尔值，您可以使用 explicitXElement 到 bool 转换:

or if you're absolutely convinced that every RegisterForComInterop will have an appropriate Boolean value you can use the explicit XElement to bool conversion:

XDocument cpo = XDocument.Load(file);
XNamespace x = "http://schemas.microsoft.com/developer/msbuild/2003";
var elements = cpo.Descendants(x + "RegisterForComInterop")
                  .Where(x => (bool) x);

如果涉及命名空间，我个人通常会选择这条路线而不是 XPath尤其是.

Personally I would usually go this route rather than XPath especially if namespaces are involved.

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