“ 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...

Well it’s that time of year again.  Time to write the performance review.  While working out at the gym this morning I had a thought… What if I shared my self-evaluation performance review with you?  After all, you are very important to...

The other day I got this tweet from Adam @ronljacobs anyway to do something like: [WebGet(UriTemplate = "{id}", IgnoreTrailingSlash = true)] want {id} and {id}/  to be the same Off hand I didn’t know the answer but now that I’m back from...

In my previous post on WorkflowServices, CanCreateInstance and Silverlight I shared with you some of the pain that I went through in building my first Silverlight / Workflow Services app. Much of this pain was just because I have not done a great deal...

Update 6/21 - there is a fix for this known issue see KB2468871 look for issue #9 I have found that when you set your app to use .NET Framework Platform Update 1 Visual Studio adds something to your configuration file. It is trying to do the right...

While working on signing assemblies you may run into a problem I encountered this morning so here goes… Problem XamlBuildTask fails when referencing a Delay Signed assembly To see this in action try the following Create a Workflow Console Application...

If you are using .NET 4 Platform Update 1 to do unit testing you may encounter this dialog box when you try to change the target framework of your test project Tip: You can press Ctrl+C on a message box to copy the text to the clipboard.  If you...

tempuri.org is the default namespace applied to WCF Services and Workflow Services.  You can and should specify your service namespace. It is recommended that you explicitly specify a name and namespace for the service contract, and an action for...

Update 12/3/2011: Microsoft.Activities is now Microsoft.Activities.Extensions When I first saw NuGet I knew I had to find a way to take advantage of this great new way to deliver code to you. It took a few months but finally the other day I decided...

If you are having trouble with a Workflow deployed in IIS with Windows Server AppFabric, the event log can be a wonderful tool to help diagnose problems. First Step: Check the Windows Application Event Log Open Event Viewer Expand Windows Logs Select...

So you want to know how the state machine really works? Take a look at the WF4 State Machine Explorer .  This sample is designed to show you how StateMachine works with activities. There are three transitions from State1. To State 2 which is triggered...

Humans Go to Control Panel / Programs / Programs and Features / View Installed Updates Use the Search Box to search the updates for KB2495593 KB2478063 Or if you prefer, search the list your self Microsoft .NET Framework 4 Platform Update 1 - Runtime...

Sometimes when using Windows Workflow Foundation (WF4) you need to create a custom WorkflowServiceHostFactory.  There are a couple of main reasons why you would want to do this. To configure the WorklfowServiceHost in some way like adding an extension...

If you want to read the AppFabric Monitoring Database from a Web Application your web app will have to have permission to login. If you try to run a web app that does not have permission you will likely see this Cannot open database "AppFabricMonitoringDB"...

I can’t count how many times this has bitten me…  You create a new Workflow Service.  You create a client app, add a service reference and boom! There is no context attached to the incoming message for the service and the current operation is...

Are you sometimes frustrated by WF/WCF? Let’s just be honest for a moment… all of us are frustrated by WF/WCF at times.  Even those of us who work on the product can probably think of a hundred ways we would like to make them better.  However...

One rather large pain point with distributed systems is versioning.  There are things you can do that make this problem better and things you can do that make it worse.  The worst thing you can do is pretend that this problem does not exist...