VB.net 使用 HtmlAgilityPack 获取 href 的 InnerText

VB.net Getting the InnerText of href using HtmlAgilityPack

提问by Marc Intes

I have now updated my code (Thanks Tim for helping me learn) which is already working but it doesn't give me the right links i want.

我现在已经更新了我的代码（感谢 Tim 帮助我学习），它已经在工作，但它没有给我想要的正确链接。

Here is my working code:

这是我的工作代码：

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim webClient As New System.Net.WebClient
        Dim WebSource As String = webClient.DownloadString("http://www.google.com.ph/search?hl=en&as_q=test&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=countryCA&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&tbs=ctr%3AcountryCA&as_filetype=&as_rights=#as_qdr=all&cr=countryCA&fp=1&hl=en&lr=&q=test&start=20&tbs=ctr:countryCA")

    Dim doc = New HtmlAgilityPack.HtmlDocument()
        doc.LoadHtml(WebSource)
        Dim links = GetLinks(doc, "test")
        For Each Link In links
            ListBox1.Items.Add(Link.ToString())
        Next
    End Sub


   Public Class Link
        Public Sub New(Uri As Uri, Text As String)
            Me.Uri = Uri
            Me.Text = Text
        End Sub
        Public Property Text As String
        Public Property Uri As Uri

        Public Overrides Function ToString() As String
            Return String.Format(If(Uri Is Nothing, "", Uri.ToString()))
        End Function
    End Class


    Public Function GetLinks(doc As HtmlAgilityPack.HtmlDocument, linkContains As String) As List(Of Link)
        Dim uri As Uri = Nothing
        Dim linksOnPage = From link In doc.DocumentNode.Descendants()
                          Where link.Name = "a" _
                          AndAlso link.Attributes("href") IsNot Nothing _
                          Let text = link.InnerText.Trim()
                          Let url = link.Attributes("href").Value
                          Where url.IndexOf(linkContains, StringComparison.OrdinalIgnoreCase) >= 0 _
                          AndAlso uri.TryCreate(url, UriKind.Absolute, uri)

        Dim Uris As New List(Of Link)()
        For Each link In linksOnPage
            Uris.Add(New Link(New Uri(link.url, UriKind.Absolute), link.text))
        Next

        Return Uris
    End Function

I am currently new to this HtmlAgilityPack, I am still learning please bear with me.

我目前是这个 HtmlAgilityPack 的新手，我还在学习，请耐心等待。

My Main Goal:

我的主要目标：

Sample link: http://www.google.com.ph/search?hl=en&as_q=test&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=countryCA&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&tbs=ctr%3AcountryCA&as_filetype=&as_rights=#as_qdr=all&cr=countryCA&fp=1&hl=en&lr=&q=test&start=20&tbs=ctr:countryCA

示例链接： http://www.google.com.ph/search?hl=en&as_q=test&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=countryCA&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&tbs=ctr%3AcountryCA&as_filetype=&as_rights=#as_qdr=all&cr=countryCA&fp=1&hl=en&lr=&q=test&start=20&tbs=ctr:countryCA

My expected link outputs which contains the word "test":

我预期的链接输出包含“测试”一词：

www.copetest.com/?
www.testofhumanity.com/
www3.algonquincollege.com/testcentre/?
www.lpitest.ca/?
testtube.nfb.ca/?
www.ieltscanada.ca/testdates.jsp?
https://www.awinfosys.com/eassessment/fsa_fieldtest.htm?

采纳答案by Tim Schmelter

You shoud use the attribute hrefinstead, also note that .NET is case-sensitive by default

您应该改用该属性href，还要注意 .NET 默认区分大小写

For Each link As HtmlNode In htmlDoc.DocumentNode.SelectNodes("//a[@href]")
   Dim href = link.Attributes("href").Value
   If href.IndexOf("test", StringComparison.OrdinalIgnoreCase) >= 0 Then
       ListBox1.Items.Add(href)
       ' or
       ListBox1.Items.Add(link.InnerText)
   End If
Next 

Here is a method that should return all links in a document as List(Of Link). Linkis a custom class with two perties, one for the text and the other for the Uri:

这是一个应该将文档中的所有链接返回为List(Of Link). Link是一个具有两个属性的自定义类，一个用于文本，另一个用于Uri：

Public Class Link
    Public Sub New(Uri As Uri, Text As String)
        Me.Uri = Uri
        Me.Text = Text
    End Sub
    Public Property Text As String
    Public Property Uri As Uri

    Public Overrides Function ToString() As String
        Return String.Format("{0} [{1}]", Text, If(Uri Is Nothing, "", Uri.ToString()))
    End Function
End Class

Public Function GetLinks(doc As HtmlAgilityPack.HtmlDocument) As List(Of Link)
    Dim uri As Uri = Nothing
    Dim linksOnPage = From link In doc.DocumentNode.Descendants()
                      Where link.Name = "a" _
                      AndAlso link.Attributes("href") IsNot Nothing _
                      Let text = link.InnerText.Trim()
                      Let url = link.Attributes("href").Value
                      Where uri.TryCreate(url, UriKind.Absolute, uri)

    Dim Uris As New List(Of Link)()
    For Each link In linksOnPage
        Uris.Add(New Link(New Uri(link.url, UriKind.Absolute), link.text))
    Next

    Return Uris
End Function

Here is the requested overload that checks if an url contains a given text:

这是检查 url 是否包含给定文本的请求重载：

Public Function GetLinks(doc As HtmlAgilityPack.HtmlDocument, linkContains As String) As List(Of Link)
    Dim uri As Uri = Nothing
    Dim linksOnPage = From link In doc.DocumentNode.Descendants()
                      Where link.Name = "a" _
                      AndAlso link.Attributes("href") IsNot Nothing _
                      Let text = link.InnerText.Trim()
                      Let url = link.Attributes("href").Value
                      Where url.IndexOf(linkContains, StringComparison.OrdinalIgnoreCase) >= 0 _
                      AndAlso uri.TryCreate(url, UriKind.Absolute, uri)

    Dim Uris As New List(Of Link)()
    For Each link In linksOnPage
        Uris.Add(New Link(New Uri(link.url, UriKind.Absolute), link.text))
    Next

    Return Uris
End Function

Editednow tested, works, use it in the following way:

编辑现在测试，工作，按以下方式使用它：

Dim site = File.ReadAllText("C:\Temp\website_test.htm")
Dim doc = New HtmlAgilityPack.HtmlDocument()
doc.LoadHtml(site)
Dim links = GetLinks(doc)
For Each Link In links
    ListBox1.Items.Add(Link.ToString())
Next