As promised, here are the demos from the precon myself and Dave Wheeler (get a blog Dave) did at Software Architect 2008. It was a fun day talking about security, WCF, WF, Windows Forms, WPF, Silverlight, Ajax, ASP.NET MVC, LINQ and Oslo

DotNetForArchitects.zip (791.24 KB)

There is a text file in the demos directory in the zip that explains the role of each of the projects in the solution

Edit: Updated the download link so hopefully the problems people have been experiencing will be resolved

I've just got back from Software Architect 2008. Its a great conference to speak at and an interesting change from speaking at hard core developer conferences like DevWeek. Thanks to everyone who attended my sessions - the slides and demos are below

SOA with WCF and WF - SOA.zip (368.43 KB)

Volta - Volta.zip (506.21 KB)

The slides and demos from the pre conference workshop on .NET 3.5 for architects that Dave Wheeler and me presented will be posted early next week. We have realised we really need a guide to what all the projects are and how they relate - so we'll add this documentation and post them

The Workflow Mapper Activity for copying data from one object to another was an interesting project for myself, Jörg and Christian. However, none of us has the cycles to turn it into the hugely valuable activity I think it could be. therefore, we have decided to publish the code on codeplex so hopefully we can get community involvement to polish the functionality.

You can find the project at

http://www.codeplex.com/WFMapperActivity

Take a look and let us know if you want to get involved in the project

I use my machine for development and research as well as teaching. Originally I only installed VS2005 and SQL Express. I later installed VS 2008. Finally I installed BizTalk (which required a full-blown SQL Server install) and thought nothing more of it.

More recently I was checking into how LINQ to SQL was doing some things and realised I couldn't find SQL Server Profiler on my machine - in fact I couldn't find any of the SQL Server tools! I googled this a bit and found this was a well known issue with installing SQL Express before SQL Server. So I resigned myself to sorting this out on the next repave.

I was talking to Kev Jones about this issue at DevWeek last week and yesterday he pops up and tells me he's solved it. Kev had the cunning idea of actually reading the SQL Server installation warning messages - which apparently tell you exactly what to do.

You can read Kev's post about it here

The demos from my DevWeek 2008 Postcon A Day of Connected Systems with VS 2008 are now here:

DayOfCS.zip (1.48 MB)

Thanks for attending the session

The demos for my DevWeek 2008 talk on a Developers Guide to Workflow are now available here:

DevGuideToWF.zip (31.23 KB)

Thanks a lot for attending the session

The demos from my DevWeek 2008 Silver talk about integrating WCF and WF are available here:

Silver.zip (107.74 KB)

Thanks for coming to the talk

The demos from my DevWeek 2008 Robust Long Running Workflow talk are now available here:

RobustLongRunning.zip (28.84 KB)

Thanks for coming to the talk.

Recently I wrote an article on Volta for the DevelopMentor newsletter DevelopMents. I concentrated on the core of what Volta is doing, IL rewriting, rather than highlight the IL to JavaScript functionality that has caught most attention. You can read the article here.

Recently I discussed creating robust multi-host workflow architectures with WF using the SqlWorkflowPersistenceService. I talked about an issue with the way workflow ownership is implemented and  showed some code that would fix the issue but that I also said was a hack. Ayende rightly pointed out that for high volume systems it would be a disaster. The point of that post was to highlight the problem.

Ideally the workflow team will fix the persistence service to recover from abandoned workflows more robustly - in the meantime the following stored procedure will unlock the abandoned workflows and make then runnable. The idea is to make this a scheduled job in the database running every few seconds - this is essentially what BizTalk does.

CREATE PROCEDURE dbo.ClearUnlockedWorkflows
AS
BEGIN
  SET NOCOUNT ON

  UPDATE InstanceState Set ownerID=null, 
                           ownedUntil=null, 
                           unlocked=1,
                           nextTimer=getdate()
  WHERE NOT ownerID is NULL and 
            ownedUntil < getdate()

  RETURN
END

The only oddity in the code is the setting of the nextTimer to the current time. The issue is that straight persistence (as opposed to unloading on a delay) sets this value to 31st Dec 9999 which is obviously not going to be reached for some time. Unfortunately the workflow will only be scheduled due to an expired timer so I have to reset the timer such that it will expire immediately. I can't think of any issues this would cause but if there's a scenario I haven't thought of all comments are welcome.

For the third year running I'm going to be speaking at BearPark's DevWeek conference. This year I actually managed to submit some breakout session titles on time too.

Wednesday 12th March

11:30 A developer’s guide to Windows Workflow Foundation
There are many challenges to writing software. Not least of these are lack of transparency of code and creating software that can execute correctly in the face of process or machine restart. Windows Workflow Foundation (WF) introduces a new way of writing software that solves these problems and more. This session explains what WF brings to your applications and explains how it works. Along the way we will see the major features of WF that make it a very powerful tool in your toolkit, removing the need for you to write a lot of complex plumbing.

14:00 Creating robust, long-running Workflows
Long-running processes have unique requirements in that they need to maintain state over process restart; Windows Workflow Foundation (WF) enables this with its persistence infrastructure. However, there are issues around hosting and activity development that require attention for long running workflows to be robust. This session looks at the design of the workflow persistence service; issues around hosting and creating full featured asynchronous activities. This session assumes some familiarity with WF.

16:00 Cross my palm with Silver – creating workflow-based WCF services
There are very good reasons for using a workflow to implement a WCF service: workflows can provide a clear platform for service composition (using a number of building block services to generate functionally richer service); workflows can manage long running stateful services without having to write your own plumbing to achieve this. This session introduces the new Visual Studio 2008 Workflow Services. This technology, previously known as “Silver”, provides a relatively seamless integration between WF and WCF, enabling the service developer to concentrate on the application functionality rather than the plumbing. This session assumes some familiarity with WF and WCF.

Friday 14th March - Postcon

A day of connected systems with Visual Studio 2008
Most businesses find themselves building applications that use two or more machines working together to produce their functionality. One of the challenges in this world, apart from the actual business logic being implemented, is connecting the different parts of the application in a way that best fits the environment the machines are places – are there firewalls in place? Are some parts of the application written on different platforms such as Java? Do the different parts of the application have to maintain their state over machine restart? Late 2006 saw Microsoft release WCF and WF to tackle some of these challenges. However, parts of the story were left untold – especially the integration between the two.
Visual Studio 2008 introduces a number of new features for writing service based software. Its features build on the libraries released as part of .NET 3.0, providing an integration layer between the two. In this pre/post conference session we start at the basics of how WCF and WF work and then look at the various integration technologies introduced in Visual Studio 2008.

So if you're attending DevWeek I hope to see you there