通过HtmlAgilityPack获取属性的值

问题描述

我想通过HtmlAgilityPack获取属性值. HTML代码:

I want to get a value of an attribute by HtmlAgilityPack. Html code:

<link href="style.css">
<link href="anotherstyle.css">
<link href="anotherstyle2.css">
<link itemprop="thumbnailUrl" href="http://image.jpg">
<link href="anotherstyle5.css">
<link href="anotherstyle7.css">

我想获取最后一个href属性.

I want to get last href attribute.

我的c#代码:

HtmlWeb web = new HtmlWeb();
HtmlAgilityPack.HtmlDocument htmldoc = web.Load(Url);
htmldoc.OptionFixNestedTags = true;
var navigator = (HtmlNodeNavigator)htmldoc.CreateNavigator();
string xpath = "//link/@href";
string val = navigator.SelectSingleNode(xpath).Value;

但是该代码返回第一个href值.

But that code return first href value.

推荐答案

在XPath之后，选择定义了href属性的link元素.然后从链接中选择最后一个:

Following XPath selects link elements which have href attribute defined. Then from links you are selecting last one:

var link = doc.DocumentNode.SelectNodes("//link[@href]").LastOrDefault();
// you can also check if link is not null
var href = link.Attributes["href"].Value; // "anotherstyle7.css"

您还可以使用last() XPath运算符

You can also use last() XPath operator

var link = doc.DocumentNode.SelectSingleNode("/link[@href][last()]");
var href = link.Attributes["href"].Value;

更新:如果要获取同时具有itemprop和href属性的最后一个元素，请使用XPath //link[@href and @itemprop][last()]或//link[@href and @itemprop](如果您要采用第一种方法).

UPDATE: If you want to get last element which has both itemprop and href attributes, then use XPath //link[@href and @itemprop][last()] or //link[@href and @itemprop] if you'll go with first approach.

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