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With the .NET framework 4.0 approaching I've started trying some stuff out. One of the things is the new runtime itself in combination with persistence. My first impressions were good, the new WorkflowInstance way of working is much easier than the previous one with the workflowruntime class that...
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Back in august I worked with a customer to build a workflow solution using Workflow 3.5. We crafted up a simple workflow where we would like to get a message into the workflow using the receive activity and then persist this call in the database, giving the caller a ticket that he can use later for reference...
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Last week I have been working on our workflow solution where someone discovered that in some cases it appeared that certain workflows did not complete and would never wake up again. It took me a while to figure out why this was the case. We host our workflows in IIS and there we use the ManualWorkflowSchedulerService...
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Everybody doing serious workflow development using Windows Workflow Foundation has probably experienced first hand that the workflow designer hosted by Visual Studio is not the most stable application ever. Every now and then you get unexplainable errors, while you didn't do anything you'd expect...
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The past two days I have been working on a performance problem we were having with a workflow implementation. The workflow was quite simple, A WCF call coming in, then registering the request data in a SQL database and return a ticket that the request was received. The ticket can be used by people to...
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Today I ran into another bug related to SQL tracking. We have a workflow that changes it's implementation based on settings from the database. So what we do is use the WorkflowChanges object and modify the activity tree and apply the changes. Nothing fancy, just simple workflow stuff fully documented...
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Today I gave a session at SDC about Practical windows workflow foundation and a session on advanced activity development where I explained the way I build te WCF activities I published at codeplex. I promised to put up my slides and code samples on my blog, so here they are: slides for the Practical...
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Today I finished some additional work I did on the WCF activities at codeplex. I added some nice features (if I may say so myself :-)) that implement automatic workflow correlation based on custom attributes applied on the operation or data contract. If you are not familiar with the activities, take...
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A while ago I was doing some technical research on WF: While my workflow was waiting for input, it also had to support some kind of timeout functionality. It also had to be possible to configure the duration of the timeout outside of the workflow (eg app.config), without the need to redeploy or restart...
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A few months ago I blogged about a bug in the serialization code in Windows Workflow Foundation[1]. The bug is that when you change a custom workflow activity that is being used in a persisted workflow, you will get weird errors like ArgumentOutOfRangeException or an error telling you an IObjectReference...
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Earlier I wrote about a bug in Windows Workflow Foundation where it was no longer possible to resume workflows that were persisted in a SQL when you change an activity while there are persisted workflows in the database. After having created a small test I can confirm it's definitly a problem with...
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A few days ago Martijn and I had a really weird problem with our SQL persistence store for Windows Workflow Foundation. Martijn was trying to build a small application that had to start all workflows with a timer, so that the timers that were expired were handled by the workflow. Somehow he got an exception...
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Finally I made it to free up some time and create a released version of the WCF Activities I have been working on for some time now. This version is fully tested and already used in multiple projects I am working on including the very demanding ones that run thousands of workflows a day! First of all...
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Last week we ran in to a nasty problem with windows workflow foundation in our project. We ran one of our load tests for more than a few hours. We noticed that after a few hours all workflows ended up as being aborted for no apparent reason. Digging further into the problem we decided that we would add...
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The past few weeks I have been updating the WCF activities I published on Codeplex frequently. But the codeplex server my project is hosted on has been out since April 11 th ! Today I was able to connect to the server again, but the history of the project is not recovered from the crash. They switched...