WPF (vb.net) 从网页到 label/text 块的文本

Question

我想从我的 HTML 页面读取文本并将其显示到我的 WPF 应用程序中的 Label 或 TextBlock 中。我该怎么做？

使用 Windows 表格我是这样做的：

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    WebBrowser1.Navigate("C:\Users\Test\Desktop\Webseite\test.htm")
End Sub

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


    Dim ImageInhalt As String
    Label1.Text = WebBrowser1.Document.GetElementById("mytext").GetAttribute("value")

    ImageInhalt = WebBrowser1.Document.GetElementById("mytext2").GetAttribute("value")

    If ImageInhalt.Contains("STOP") Then
        PictureBox1.Image = My.Resources._stop
    End If

End Sub
End Class

HTML 页 (test.htm)

<input type="text" name="userInfoNav" value="Hallo"/><br/>"

现在非常感谢您的帮助

Answer 1

您必须将 URL 或文件的 HTML 内容加载到 mshtml.HTMLDocument 中。然后，您可以使用类似 JavaScript 的语法处理 DOM 对象。

需要参考 Microsoft.mshtml.dll。

C#

partial class MainWindow : Window
{
  private mshtml.HTMLDocument HtmlDocument { get; set; }

  public async Task SetTextBoxTextAsync(string filePath, string id)
  {
    await UpdateHtmlDocumentAsync(filePath);
    string value = GetHtmlElementValueById(id);
    this.TextBlock.Text = value;
  }

  private async Task UpdateHtmlDocumentAsync(string filePath)
  {
    string htmlContent = await File.ReadAllLinesAsync(filePath);
    this.HtmlDocument = new HTMLDocument();
    (this.HtmlDocument as IHTMLDocument2).write(htmlContent);
  }

  private string GetHtmlElementValueById(string elementId)
    => this.HtmlDocument.getElementById(elementId).innerText;
}

VB.NET

Partial Class MainWindow
    Inherits Window

    Private Property HtmlDocument As mshtml.HTMLDocument

    Private Async Function SetTextBoxTextAsync(ByVal filePath As String, ByVal id As String) As Task
        Await UpdateHtmlDocumentAsync(filePath)
        Dim value As String = GetHtmlElementValueById(id)
        Me.TextBlock.Text = value
    End Function

    Public Async Function UpdateHtmlDocumentAsync(ByVal filePath As String) As Task
        Dim htmlContent As String = Await File.ReadAllLinesAsync(filePath)
        Me.HtmlDocument = New HTMLDocument()
        (TryCast(Me.HtmlDocument, IHTMLDocument2)).write(htmlContent)
    End Function

    Public Function GetHtmlElementValueById(ByVal elementId As String) As String
        Return Me.HtmlDocument.getElementById(elementId).innerText
    End Function
End Class

备注

如果您对呈现内容感兴趣，请使用 WebBrowser 控件。它有一个 Document 属性，您可以将其转换为 mshtml.HTMLDocument。由于 WebBrowser 是一个重实例，因此只有在打算渲染 HTML 时才应使用它。否则如上所示手动构建 mshtml.HTMLDocument。

WPF (vb.net) 从网页到 label/text 块的文本

WPF (vb.net) Text from web page to label/text block

vb.net

wpf

备注