Text span id Fehler

Question

mit bekomme ich den Text aus dem span id "hkoTemp" und hier greifen will, ist der Code:

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load 
    Dim wb As WebBrowser = New WebBrowser 
    wb.Navigate(New Uri("http://www.hko.gov.hk/contentc.htm")) 
    Dim temp = wb.Document.GetElementById("hkoTemp").GetAttribute("innerText") 
    MsgBox(temp) 
    End Sub 

Wenn ich versuche, es zu laufen, wird es ein Fehler auf
Dim temp = wb.Document.GetElementById("hkoTemp").GetAttribute("innerText")

, wie ich es beheben kann?

Answer 1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
    Dim wb As WebBrowser = New WebBrowser() 
    wb.AllowNavigation = True 
    AddHandler wb.DocumentCompleted, New WebBrowserDocumentCompletedEventHandler(AddressOf wb_DocumentCompleted) 
    wb.Navigate(New Uri("http://www.hko.gov.hk/contentc.htm")) 
End Sub 

Private Sub wb_DocumentCompleted(sender As Object, e As WebBrowserDocumentCompletedEventArgs) 
    ' wb.Document is not null at this point 
    Dim wb As WebBrowser = sender 
    Dim temp = wb.Document.GetElementById("hkoTemp").GetAttribute("innerText") 
    MsgBox(temp) 
End Sub