循环遍历XPathNodeIterator问题

发布于 2024-12-06 00:50:11 字数 691 浏览 1 评论 0原文

我创建了一个 XPathNodeIterator，其中包含一些短的 XML 段（每个段都有一个文件描述）：

XPathNodeIterator segments = node.SelectDescendants("Segment", node.NamespaceURI, false);

现在，当尝试循环它们时，似乎每次都只选择第一个段。以下是我尝试过的循环的两个版本（仅以文件/文件类为例）：

while (segments.MoveNext())
{
    File f = GetSingleFileDataFromSegment(segments.Current);

    files.Add(f);
}

另一种尝试：

foreach (XPathNavigator seg in segments)
{
    File f = GetSingleFileDataFromSegment(seg);

    files.Add(f);
}

当使用 Watch 或 Quickwatch 查看循环中的单个片段时，它看起来应该如此，所有不同的片段都在一次 - 但最终结果是“文件”包含第一个段的多个副本。

这是 XPathNodeIterator 的正常行为吗？或者这里缺少什么？我目前正在使用 .NET Framework 3.5。

原文

I've created a XPathNodeIterator that contains a few short XML segments (each with a file description):

XPathNodeIterator segments = node.SelectDescendants("Segment", node.NamespaceURI, false);

Now, when trying to loop them, it seems that only the first segment is picked every time. Here are two versions of the loops I've tried (File/Files classes only for example):

while (segments.MoveNext())
{
    File f = GetSingleFileDataFromSegment(segments.Current);

    files.Add(f);
}

Another try:

foreach (XPathNavigator seg in segments)
{
    File f = GetSingleFileDataFromSegment(seg);

    files.Add(f);
}

When viewing a single segment in a loop with Watch or Quickwatch, it looks as it should, all different segments are selected one at a time - but end result is that "files" contain multiple copies of the first segment.

Is this normal behavior with XPathNodeIterator? Or is something missing here? I'm currently using .NET Framework 3.5.

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全部不再 2024-12-13 00:50:11

问题出在 GetSingleFileDataFromSegment 方法中，该方法使用 XPath 来获取正确的段。段属性中包含命名空间，这需要使用命名空间管理器。

有错误的 XPath 表达式：

f.Location = seg.XPathSelectElement("//*[local-name()='Location']").Value;

更正版本：

System.Xml.XmlNamespaceManager nsmanager = new System.Xml.XmlNamespaceManager(seg.ToXmlDocument().NameTable);
nsmanager.AddNamespace("ns", seg.Elements().FirstOrDefault().GetDefaultNamespace().NamespaceName);
f.Location = seg.XPathSelectElement("./ns:Location", nsmanager).Value;

上面的代码位于接收段作为参数的方法中。

The problem was in GetSingleFileDataFromSegment -method, which used XPath to get the proper segment. The segment attributes had namespaces in them, and that required the use of a NamespaceManager.

Faulty XPath expression:

f.Location = seg.XPathSelectElement("//*[local-name()='Location']").Value;

Corrected version:

System.Xml.XmlNamespaceManager nsmanager = new System.Xml.XmlNamespaceManager(seg.ToXmlDocument().NameTable);
nsmanager.AddNamespace("ns", seg.Elements().FirstOrDefault().GetDefaultNamespace().NamespaceName);
f.Location = seg.XPathSelectElement("./ns:Location", nsmanager).Value;

Code above was in the method that received the segment as parameter.

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