Displaying XML in WebBrowser control

Posted by Marcus Hammarberg on December 18, 2007
This is one of those "how can this be hard stuff", and after checking the Net i couldn't find anything much about how to do it.

The case is as follow; say that you have some XML that you want to display to the user. What better way than to use the nice format used by Internet Explorer itself. So you use the WebBrowser control in Visual Studio 2005 and simply pour the XML into the DocumentText-property... But hey - where are my tags? Where is the formatting?

So how do you display XML in the WebBrowser then? Well the simplest way is to save the XML-file to disk and simply start it with Process.Start. This might also be quite enough for some solutions.

But if you need to do this over and over you want to work with the XML-file in memory. In order to get the nice formatting you'll need to do some XML transformations also.

So get the IE XML style sheet for displaying XML (from here for example: http://www.biglist.com/lists/xsl-list/archives/200003/msg00769.html) and import it as a resource in your project. You could also hold it as a string variable but that is not as nice.

The following method does the transformation for you:

''' Transforms the XML-string with the sent-in XSL-string

''' the xml to transform
''' the xsl to use for the transformation
''' a memorystream with the result of the transformation
''' An example of a call to set the XML in a webbrowser
''' WebBrowser1.DocumentStream = TransformXML(xml, My.Resources.PositionsDetaljer)

Friend Shared Function TransformXML(ByVal xmlString As String, ByVal xlsString As String) As MemoryStream
Dim memStream As MemoryStream = Nothing
' Create a xml-document from the sent-in xml-string
Dim xmlDoc As New XmlDocument

' Load the xls into another document
Dim xslDoc As New XmlDocument

' Create a transformation
Dim trans As New XslCompiledTransform

' Create a memory stream for output
memStream = New MemoryStream()

' Do the transformation according to the XSLT and save the result in our memory stream
trans.Transform(xmlDoc, Nothing, memStream)
memStream.Position = 0
Catch ex As Exception
Throw ex
End Try

Return memStream
End Function

The final part is almost trivial:

WebBrowser1.DocumentStream = TransformXML(m_message, My.Resources.IEXMLDefaultStyle)

One last gotcha though - don't set any of the Document properties in the constructor of the form. Do it in the Load-event handler or later.

Published by Marcus Hammarberg on Last updated