Solved

Having trouble loading content in to a MSHTML.Document from a windows form.

Posted on 2008-10-15
1
378 Views
Last Modified: 2013-11-25
I have three .net projects, an ASP.net web app, a Class Library and a Windows Form app. Both the Windows app and the ASP.net app reference the class library. However the class library is behaving differently depending on which application is calling it.

The class library (.dll) contains a function called LoadHtmlIntoDoc. This function accepts a string and loads it in to a MSHTML.HTMLDocumentClass, the HTMLDocumentClass is then used for parsing (it is never used in a UI).

I have a couple versions of the function, both version of the function are shown below (although abbreviated for simplicity....)

Initially this library was developed for use with an ASP.net web application, and BOTH functions below work great when they are called from the ASP.net application. However when the same exact functions are called from the Windows Form application neither of them work. The ASP.net app and the Windows app both link to the same exact .dll, and the augment passed to the functions is identical in both cases; but I'm getting very different results.

When Version 1 of the function is called from the Windows Form it runs, but just an empty document is loaded, So that no matter what I pass to the LoadHtmlIntoDoc function, the following is always true after the function runs :
Doc.documentElement.outerHTML = "<HTML><HEAD></HEAD><BODY><P>&nbsp;</P></BODY></HTML>"


When Version 2 of the function is called from the Windows Form iDoc2.readyState is "loading" forever, causing an infinite loop/lockup...

I have no clue why this .dll would behave differently depending on which type of application is linking to it. I really need this library to function correctly when it is called from a Windows application AND an ASP.net application.

Here is the function I'm using : (two versions of the same function, both work when called from ASP.net, neither work when called from the Windows app.)

Any help if VERY much appreciated!!
'Version 1:
 
Public Function HTMLDocumentClass(ByVal strHTML as string) As Boolean
 
	Dim hr As Integer = WinApis.CreateStreamOnHGlobal _
(Marshal.StringToHGlobalAuto(strHTML), True, stream)
 
	If (hr <> Hresults.S_OK) OrElse (stream Is Nothing) Then
		Return false
	End If
 
	Doc = New HTMLDocumentClass()
 
	persistentStreamInit = TryCast(Doc, IPersistStreamInit)
 
	If persistentStreamInit IsNot Nothing Then
		persistentStreamInit.InitNew()
		persistentStreamInit.Load(stream)
		persistentStreamInit = Nothing
		ret = True
	End If
 
	stream = Nothing
 
	Return True
 
End Function
 
 
'Version 2:
Public Function HTMLDocumentClass(ByVal strHTML as string) As Boolean
 
	Dim Doc As IHTMLDocument2
			
	Doc.clear()
	Doc.write(strHTML)
	Doc.close()
 
	While (Doc.readyState <> "complete" And _
          iDoc2.readyState <> "interactive")
		System.Threading.Thread.Sleep(0)
		System.Threading.Thread.Sleep(100)
		System.Threading.Thread.Sleep(0)
	End While
			
	Return True
 
End Function

Open in new window

0
Comment
Question by:minermadison
1 Comment
 
LVL 1

Accepted Solution

by:
minermadison earned 0 total points
ID: 22723366
I figured out the problem. The difference between the two apps was the thread apartment state. I changed the thread in the windows app to MTA and now it works.
0

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In my previous two articles we discussed Binary Serialization (http://www.experts-exchange.com/A_4362.html) and XML Serialization (http://www.experts-exchange.com/A_4425.html). In this article we will try to know more about SOAP (Simple Object Acces…
For a while now I'v been searching for a circular progress control, much like the one you get when first starting your Silverlight application. I found a couple that were written in WPF and there were a few written in Silverlight, but all appeared o…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question