One thing that many web sites do is to verify email addresses by sending you an email to complete registration.  I decided to build a Registration system for ASP.NET MVC using Windows Workflow Foundation. When you create a new ASP.NET MVC web site...

Sometimes you have a workflow service that is misbehaving in a production environment.  How do you figure out what is going on when you can’t attach a debugger? The solution is to use Workflow Tracking.  There are two alternatives you can try...

Try this… Create a new ASP.NET Web Application (MVC or Web Forms).  Then add a new a WCF Workflow Service to your web project. Now try to add a service reference to your workflow service.  It fails with an error. There was an error downloading...

In my previous posts I’ve written about my experiences with WorkflowServices and Silverlight. Troubleshooting Workflow Services / Silverlight Using Workflow Services and Silverlight Together WorkflowServices, CanCreateInstance and Silverlight Problem...

I was doing some work on my Contoso HR Workflow Services sample application today when for some strange reason things were not working at all.  I found that when I tried to send a message to the Workflow Service from the ASP.NET code I got this exception...

If you install the Visual Studio 11 Preview release on a machine that has .NET 4 Platform Update 1 installed you will find that projects targeting .NET 4 Platform Update 1 will fail to build properly.  The error you will get is 'System.Activities...

If you need a quick and simple way to manually test your WorkflowService the WCF Test Client makes it simple but there are a few tips that will make your life much easier. Tip: Add the WCF Test Client to your Visual Studio Tools menu Select Tools / External...

From time to time I’ll hear from somebody who is trying to use a WCF Workflow Service with Silverlight as the client and they are getting this exception. System.ServiceModel.CommunicationException was unhandled by user code Message=An error occurred while...

If you are using Microsoft.Activities.UnitTesting.XamlInjector to mock activities you may run into an error like this. Test method XamlInjectorRepro.Test.UnitTest1.TestMethod1 threw exception: System.Xaml.XamlObjectWriterException: Cannot create unknown...

The Windows Workflow Foundation (WF4) - Custom Activity Designer sample demonstrates how you can build an activity and activity designer.  It includes three projects MyActivityLibrary - The activity library project MyActivityLibrary.Design - The...

Today I’ve been fixing up the build system for Microsoft.Activities and Microsoft.Activities.UnitTesting.  Over time I’ve been using a combination of strange tools and batch files to build things but it became such a mess I decided to take the time...

You know those little tools you build to help in your development?  The ones that you slapped together in a hurry and might not work all the time but you put up with them because you don’t want to take the time to fix them?  Well CleanProject...

  The NuGet team has recently added the ability to store the package icon URL in the nuspec file. Now I need to have a public copy of the icon available somewhere on the web.  I tried putting it on CodePlex but the URI uses QueryString parameters...

I love Task<T>.  It has to be one of the finest innovations in the framework in the past few years.  Recently I was reviewing some old WCF documentation How to: Implement an Asynchronous Service Operation which was probably written in...

In my previous posts I’ve been arguing that you can implement Task Parallelism with Windows Workflow Foundation (WF4).  This post is a part of a series on WF, Parallelism and Threading Windows Workflow Foundation (WF4) Activities and Threads The...

In my last post The Workflow Parallel Activity and Task Parallelism I said that you can implement Task Parallelism with Windows Workflow Foundation.  In this post I want to explore some of the differences between the Parallel Activity in System.Workflow...

“ Task parallelism (also known as function parallelism and control parallelism ) is a form of parallelization of computer code across multiple processors in parallel computing environments. Task parallelism focuses on distributing execution processes...

Most of the time in software when we say “Parallel” we mean that multiple threads are being used to do work concurrently.  Because of this, many customers ask if the Parallel activity works this way in Windows Workflow Foundation.  I know there...

With Windows Workflow Foundation (WF4) you can author activities in Code or XAML.  Each has advantages and disadvantages Visibility Advantage – XAML You can author them in the Workflow Designer.  Here is a activity I’ve been working with today...

Recently I was contacted by a customer who had read my posts on Versioning and was investigating some interesting behavior of activity designers (more on this in a future post).  But this discussion got me to thinking.  As I pointed out in my...

This morning I saw a message post on the .NET 4 Windows Workflow Foundation Forum titled Load XAMLX from database .  I’ve been asked this question many times. How can I store my Workflow Service definitions (xamlx files) in a database with IIS and...

Lots of people create state machines.  There are many examples on the web of people who are building class libraries to make it easy to create a state machine.  These people typically don’t need (or want) to use a workflow designer or see a...

Way back in September 2009 I wrote WF4: Passing Arguments to Activities .  In the years since I’ve learned a few things. Download code for this post Windows Workflow Foundation (WF4) - Workflow Arguments Example Watch Out for Initialization Syntax...

For background on this issue see WF4 How To Invoke a Child Workflow as XAML .  Thanks to rfcdejong who recently logged an issue on our http://wf.CodePlex.com site Child activity's ignore the Tracking Participant / Tracking Profile ? Because of this...

It’s been a long while but in the old WF 3.5 days as I recall there was this funky binding thing that allowed you to pass values from the output of one activity directly to the input of another activity.  Windows Workflow Foundation (WF4) does not...