Convert html string to HTMLDocument for parsing

**stateofidleness** · Apr 2nd, 2011, 04:41 PM

Gents,
I'm able to retrieve the source code of a web page and store it in a string variable. I would like to cast that string variable into an HTMLDocument if possible, to make parsing its elements much easier.

How can I do this?

**.paul.** · Apr 2nd, 2011, 04:49 PM

you can declare a webbrowser control in code + use it without adding it to a form:

vb Code:

Dim wb As New WebBrowser
wb.DocumentText = "your html string"
Dim doc As HtmlDocument = wb.Document

**stateofidleness** · Apr 2nd, 2011, 04:54 PM

ah ok. i was close!

Problem I'm seeing is that my variable DOES hold valid html (an entire page's worth), but when I set the DocumentText equal to it, it strips everything out and leaves only "<HTML></HTML>" so any future calls to it generate a Null Reference Exception..

Here's my code:

vb Code:

Try
            'updates will hold the HTML Source code (verified working)
            updates = getUpdates(classURL)
            'Now scrape it
            Dim wb As New WebBrowser
            With wb
                .DocumentText = updates
                .ScriptErrorsSuppressed = True
            End With
            MsgBox(wb.DocumentText)
            Dim doc As HtmlDocument = wb.Document
 
            Dim element = doc.GetElementById("forumLabel" & txtClassID.Text).InnerText
            If element IsNot Nothing Then
                MsgBox(element)
            End If
 
        Catch ex As Exception
            MsgBox("Appears something failed: " & ex.ToString)
        End Try

**.paul.** · Apr 2nd, 2011, 04:57 PM

what does:

vb Code:

MsgBox(wb.DocumentText)

return?

**stateofidleness** · Apr 2nd, 2011, 04:58 PM

that returns the "<HTML></HTML>" , but in the debugger, if I hover over "updates", I see ALL the html

**.paul.** · Apr 2nd, 2011, 05:17 PM

ok. try this:

vb Code:

Dim wb As New WebBrowser
wb.ScriptErrorsSuppressed = True
Dim doc As HtmlDocument = wb.Document.OpenNew(True)
doc.Write("your html string")

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