得到< a>带有vag.net的htmlagilitypack的标签和属性

问题描述

我有这个代码

Dim htmldoc As HtmlDocument = New HtmlDocument()
htmldoc.LoadHtml(strPageContent)
Dim root As HtmlNode = htmldoc.DocumentNode

For Each link As HtmlNode In root.SelectNodes("//a")
    If link.HasAttributes("href") Then doSomething() 'this doesn't work because hasAttributes only checks whether an element has attributes or not
Next

但出现错误 Object reference not set to an instance of an object.

该文档至少包含一个锚标签?如何检查属性是否退出?

the document contains at least one anchor-tag? how do i check if an attribute exits?

我尝试了这个if link.HasAttributes("title") then并遇到了另一个错误

i tried this if link.HasAttributes("title") then and get another error

Public ReadOnly Property HasAttributes() As Boolean' has no parameters and its return type cannot be indexed.

推荐答案

如果HtmlAgilityPack支持此XPATH选择器，则可以将//a替换为//a[@href]

If HtmlAgilityPack supports this XPATH selector, you can replace //a with //a[@href]

For Each link as HtmlNode In root.SelectNodes("//a[@href]")
    doSomething()
Next

否则，您可以使用Attributes属性:

Otherwise, you can use the Attributes property:

For Each link as HtmlNode In root.SelectNodes("//a")
    If link.Attributes.Any(Function(a) a.Name = "href") Then doSomething()
Next

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