Visual Basic HTML Agility Pack如何从表格单元格中获取图像

时间:2014-01-23 12:39:58

标签: vb.net image extract html-agility-pack

希望有人可以提供帮助,因为我花了很多时间试图解决这个问题。我正在使用敏捷包从表中提取数据并将其放入数据网格中(数据网格并不重要,我只是使用它来查看提取是否有效)。无论如何,在表格的第一列中包含缩略图。我可以使用下面的代码提取所有文本,但我不知道如何从第一列中提取图像......任何人都可以帮忙吗?

PS我已将网页保存为MHL文件,因为无法直接从中提取任何数据 - 我认为这与网站安全/凭据有关。不知道我是否让自己变得更容易或更难。

Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

    ' '' original cods ***************************************
    Dim Web As New HtmlAgilityPack.HtmlWeb
    Dim Doc As New HtmlAgilityPack.HtmlDocument
    Dim RowCount As Integer = 1



    '   Doc = Web.Load("https://firefly.cardinalnewman.ac.uk/home/my")

    Doc.Load("E:\table.mht")


    Dim tables As HtmlAgilityPack.HtmlNodeCollection = Doc.DocumentNode.SelectNodes("//table")
    Dim img As HtmlAgilityPack.HtmlNodeCollection = Doc.DocumentNode.SelectNodes("//table")
    Dim Links As HtmlAgilityPack.HtmlNodeCollection = Doc.DocumentNode.SelectNodes("//table")
    Dim rows As HtmlAgilityPack.HtmlNodeCollection = tables(0).SelectNodes("//*[@id=HomeMyStudents]")


    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[1]")
        RowCount = RowCount + 1

        DGV.Rows.Add(Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing)

    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[2]")
        RowCount = RowCount + 1
        '     DGV.Rows(RowCount).Cells(1).Value = somehow insert image
        ' this is the section where I need to grab the image in each cell and either save or place in my datagrid


    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[3]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(2).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[4]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(3).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[5]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(4).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[6]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(5).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[7]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(6).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[8]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(7).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[9]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(8).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[10]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(9).Value = table.InnerText
    Next
    RowCount = 0
    For Each table As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='HomeMyStudents']/tbody/tr['RowCount']/td[11]")
        RowCount = RowCount + 1
        DGV.Rows(RowCount).Cells(10).Value = table.InnerText
    Next




End Sub  

1 个答案:

答案 0 :(得分:0)

所以,大概这些图像看起来像是:

<img src="whatever.jpg"/> 
在标记中,对吗?

HAP将允许您使用类似

的内容来抓取图像节点
... .SelectNodes("./img") 

对于路径:

... .Attributes("src").Value()

从那时起,我不知道任何特定的HAP功能允许您实际执行这样的任何HTTP请求,因此您将需要WebClient

Dim wc as new WebClient 

wc.DownloadFile(StringContainingThatSrcValue, PathToSaveFileTo) 

HTH!