vb.net selectnode 的 htmlagilitypack 循环

Question

我制作了一个 link 的数组

Dim horof As String = "A B C D"
    Dim alphabarray As String() = horof.Split(New Char() {" "c})
    Dim urls() As String = alphabarray.Select(Function(o) "http://somelink/list-" & o).ToArray()

输出是这样的

http://somelink/list-A
http://somelink/list-B
http://somelink/list-C
http://somelink/list-D

我为每个 link 做了 webrequest 像这样：

 For i As Int32 = 0 To urls.Length - 1
        Dim wRequest As WebRequest
        Dim WResponse As WebResponse
        wRequest = FtpWebRequest.Create(urls(i))
        WResponse = wRequest.GetResponse
        Dim SR As StreamReader
        SR = New StreamReader(WResponse.GetResponseStream)
        urls(i) = SR.ReadToEnd
 Next

现在我有 html 字符串数组中所有 link 的来源，即 urls 我想使用 htmlagilitypack 来 selectnodes 来自数组中的每个 html 源

Dim htmlDoc As New HtmlDocument()
htmlDoc.LoadHtml(urls) 
Dim wantednode = htmlDoc.DocumentNode.SelectNodes("Xpath")

但是没用

我试着把它放在同一个循环中

        Dim htmlDoc As New HtmlDocument()
        Dim wantednode As HtmlNodeCollection
For i As Int32 = 0 To urls.Length - 1
        Dim wRequest As WebRequest
        Dim WResponse As WebResponse
        wRequest = FtpWebRequest.Create(urls(i))
        WResponse = wRequest.GetResponse
        Dim SR As StreamReader
        SR = New StreamReader(WResponse.GetResponseStream)
        urls(i) = SR.ReadToEnd
        htmlDoc.Load(urls(i))
        wantednode = htmlDoc.DocumentNode.SelectNodes("Xpath")
next

这个也没用如何制作 wantednode = htmlDoc.DocumentNode.SelectNodes("Xpath") 的循环对于 urls 数组

中的每个 html 代码

urls 数组中的每个 html 代码都是这样的，来自

        <body>
          <div class="list_body">

            <ul class="listing">

                <li>
                    <a href="http://wanted1.com" title="">title1 </a>                                               
                     </li>
                <li>
                    <a href="http://wanted2.com" title="">title2  </a>                             
                     </li>
                <li>
                    <a href="http://wanted3.com" title="">title3  </a>                                                
                     </li>
                <li>
                    <a href="http://wanted4.com" title="">title4   </a>                                                                       
                     </li>
                <li>
                    <a href="http://wanted5.com" title="">title5  </a>                                                                                               
                     </li>
                <li>
                    <a href="http://wanted6.com" title="">title6   </a>                                                                                                
                     </li>
            </ul>

          </div>
       </body>

我希望 http://wanted2.com link 在 urls

的每个字符串中

Answer 1

这是我使用的一些库代码：

Public Function Web_Request_Response(URL As String) As String
    Try
        Dim myRequest As HttpWebRequest
        Dim myResponse As HttpWebResponse
        Dim sr As StreamReader
        Dim sResponse As String = ""
        myRequest = CType(WebRequest.Create(URL), HttpWebRequest)
        myResponse = CType(myRequest.GetResponse(), HttpWebResponse)
        sr = New StreamReader(myResponse.GetResponseStream())
        sResponse = sr.ReadToEnd.ToString
        Return sResponse
    Catch ex As Exception
        LogMsgBox(ex, ex.Message, , "WebRequest_Responce Error")
        Return ""
    End Try
End Function

与您的通话略有不同。也许与类型转换有关？ FTP 与 HTTP?

很好地使用了 Linq。

您可以节省一些输入时间：

Dim alphabarray As String() = horof.Split(New Char() {" "c})
--- same as ---
Dim alphabarray As String() = horof.Split({" "c})
 or
Dim alphabarray As String() = horof.Split(" ")

Answer 2

你应该使用 HtmlDocument.LoadHtml() 而不是 HtmlDocument.Load()，因为你想从 [=18] 填充 HtmlDocument =] 字符串：

'urls(i) value has been replaced with HTML string by the following line..
urls(i) = SR.ReadToEnd
'..so next, you need to use `LoadHtml()`
htmlDoc.LoadHtml(urls(i))

wantednode = htmlDoc.DocumentNode.SelectNodes("Xpath")

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