Part 1 Part 2 Part 3 Part 4 In the previous blog posts we made sure we could have multiple versions of the same workflow running side by side. This ability is one of the more powerful concepts of WF and a real must have for long running business applications. A quick recap. Always version your assemblies by giving them a strong name. Make sure the runtime can find each version of the assembly by pointing the CLR to the right version using the configuration\runtimeassemblyBinding\dependentAssembly\assemblyIdentity\codeBase

You may recall my previous posts about using the TransactionScopeActivity within a ReceiveActivity and all the nasty issues we ran into. Just in case you want to read them again: one , two and three . As it turn out this is an intentionally not supported scenario at the moment. If we read the docs for the ReceiveActivity we can find the following note: To ensure that persistence performs properly and does not persist transient messages, make sure that child activities of the ReceiveActivity do not

Part 1 Part 2 In the first article of this series I demonstrated how to get multiple versions of a workflow running side by side in the same workflow runtime. The most important thing was that you need to keep every version of the assembly around and use the assemblyBinding element in the app.config to let the runtime know where each version was on disk. Once done life was good In the second part I demonstrated how a HandleExternalEventActivity was version dependent and you needed to use the version

Part 1 Part 2 In my previous post I demonstrated how to keep multiple versions of an assembly around and how to use the assemblyBinding element in the app.config to let the runtime load multiple versions of a worklfow. In the end we had both workflows, the first in assembly 1.0.0.0 and the second in assembly 2.0.0.0, running and life seemed to be good So is there more to write on the subject? Yes unfortunately there are still some potential problems that need to be addressed . The pitfalls of External

One of the cool features of Windows Workflow Foundation is that it allows long running processes. And not just long running as in a few minutes but really long running as in a few years . This is possible true the use of the SqlWorkflowPersistenceService, or in fact any derived class from WorkflowPersistenceService, which is going to save the state of a workflow to disk when it is not actually busy. So that is pretty cool but it is kind of unlikely that your programs are not going to change over

consider every amount larger that 100 large. Hmm not much, lets change that to 1000 instead of 100... = (CodePrimitiveExpression)expression.Right; primitive.Value = 1000; ApplyWorkflowChanges(changes); Easy once

In this post I demonstrated how to create IronPython objects and call them from strongly typed .NET code. So suppose we want to do so with Windows Workflow Foundation where could we use this? Well the most obvious place would be a runtime service . The example below uses a very simple message that needs to be displayed but it is easy to see how to same concept could be applied in other places. But first the basics. I have created a very simple custom DisplayMessageActivity like this: public partial

.NET Reflector, by Lutz Roeder, must be one of the most useful tools I have when developing .NET code. Usually it is the first thing I install right after Visual Studio not even waiting until I need it because I know I will. So the big news is that Red Gate, makers of the Ants profiler and lots of other tools, are taking over from Lutz Roeder and will continue developing .NET Reflector. Interesting move and I hope this means a bright future for the .NET Reflector. Read more about this here . Enjoy!

Windows Workflow Foundation, WF for short, is one of the technologies I work a lot with and as a consequence I own several books about WF. Comparing this book with the others I can only say it is one of the best books you can get on the subject. It has a good coverage of almost all the subject you are going to need to know. Not only is there a good coverage but the explanation and examples are very clear. Now there are a few thing missing from the book. As it was written with the .NET framework 3.0

It is available from the subscriptions download at http://msdn.microsoft.com/en-us/subscriptions/default.aspx Get it while it is hot Enjoy!