WebBrowser中的VB.NET SetAttribute不起作用

Question

我之前做了一些研究，但所有答案都不起作用。 “value”属性存在于元素中，但不出现在webBrowser中，也不出现在输入中。这是我的代码，直到那时，我需要webBrowser来读取一个html文件，然后从数据库的输入中加载你的答案或值。

PS：我的应用程序是实时构建的，屏幕上没有webbrowser控件，它是在读取html文件后不久创建的，只有它被放在一个面板中。

    Dim webBrowser As WebBrowser = New WebBrowser
    Dim _doc As HtmlDocument
    Dim htmlPath As String = "C:\ePrimeCare\Platis\Debug\Protocolos\" + 
    nomeProtocolo + "_" + idSistema.ToString() + ".html"
    webBrowser.ScriptErrorsSuppressed = True
    webBrowser.Navigate(htmlPath)
    _doc = webBrowser.Document.OpenNew(False)
    'webBrowser.DocumentText = IO.File.ReadAllText(htmlPath).ToString()
    'webBrowser.Document.OpenNew(False)
    'RetornaRespostasAnteriores(idSistema, idFicha, nomeProtocolo, _doc, Convert.ToDateTime(dtVisita))
    _doc.Title = nomeProtocolo
    _doc.Write(IO.File.ReadAllText(htmlPath).ToString())
    Dim carregaRespostas As CarregarRespostaProtocoloHTML = New CarregarRespostaProtocoloHTML
    Dim respostas As DataTable = carregaRespostas.BuscarRespostasProtocoloAnterior(idFicha, idSistema, dtVisita)

    Dim idopcaoitem As String = 0
    Dim idsetitem As String = 0
    Dim value As DataRow()
    Dim strArr As String()
    For Each element As HtmlElement In _doc.GetElementsByTagName("input")
        Dim type As String = element.GetAttribute("type")
        Select Case type
            Case "text"
                strArr = element.GetAttribute("id").Split("_") 'For get the two ids
                idopcaoitem = strArr(0)
                value = respostas.Select(("IDOPCAOITEM = " + idopcaoitem.ToString()))
                If value.Length > 0 Then
                    element.SetAttribute("value", value(0)(2).ToString())'Here i try to set the value, but does not work
                End If
            Case "radio"
                Debug.WriteLine("Input de radio")
            Case "checkbox"
                Debug.WriteLine("Input de checkbox")
            Case "hidden"
                Debug.WriteLine("Input de hidden")
            Case Else
                Debug.WriteLine("Outro input")
        End Select
    Next
    _doc.Write(IO.File.ReadAllText(htmlPath).ToString())
    webBrowser.Refresh(WebBrowserRefreshOption.Completely)
    webBrowser.Dock = Dock.Fill
    pnlMain.Controls.Add(webBrowser)

Answer 1

所有文档重写和最后完成的刷新都将覆盖您对其所做的任何更改。

'Either of these will revert the document back to its original state.
_doc.Write(IO.File.ReadAllText(htmlPath).ToString())
webBrowser.Refresh(WebBrowserRefreshOption.Completely)

你甚至不需要打电话给_doc.Write()，因为WebBrowser1.Navigate(htmlPath)可以正常工作。

新代码：

Dim webBrowser As New WebBrowser 'Shorthand statement.
Dim _doc As HtmlDocument
Dim htmlPath As String = "C:\ePrimeCare\Platis\Debug\Protocolos\" + 
nomeProtocolo + "_" + idSistema.ToString() + ".html"
webBrowser.ScriptErrorsSuppressed = True
webBrowser.Navigate(htmlPath)
_doc = webBrowser.Document 'Removed OpenNew().
_doc.Title = nomeProtocolo

Dim carregaRespostas As New CarregarRespostaProtocoloHTML 'Another shorthand statement.
Dim respostas As DataTable = carregaRespostas.BuscarRespostasProtocoloAnterior(idFicha, idSistema, dtVisita)

(...your variables...)

For Each element As HtmlElement In _doc.GetElementsByTagName("input")

    (...your code...)

Next

'(Removed _doc.Write() and Refresh() since they will undo all changes)

webBrowser.Dock = Dock.Fill
pnlMain.Controls.Add(webBrowser)