Workflow Insights: Introduction
This week I am starting a new series of articles to give you guys more insight in the Windows Workflow Foundation framework. The Windows Workflow Foundation (WF) is a framework which was released last year as part of the .NET Framework 3.0 alongside the Windows Presentation Foundation (WPF) and the Windows Communication Foundation (WCF). It allows you to model workflows: flows of logical (and easy-to-understand) work units. Here’s a basic example.
The units are represented by blocks, so-called “activities”, you can use by dragging them on your workflow designer. And right there, you get the main advantage of workflows. This methodology of creating a process by assembling logic building blocks together is pretty powerful. Especially when you envision a developer sitting down next to a business guy and interactively building the workflow together with him in just a couple of hours. And this without loosing track of the objective as they are working with small logical blocks.
For example, you can use a Send Email activity without having to know how it is actually sent or which methods you have to use. You just fill in a couple of properties and off you go. The big hick-up, unfortunately, is that there aren’t many blocks to choose from. So, we have to create them ourselves. And this is where the frustration begins. Most of the time the business has these complex rules set up and wants them translated to workflow technology. Creating all of these abstractions of the inner workings to the actual logic they’re producing, can be quite hard and sometimes just plain impossible. Why? Well, we have this framework we have to work around, which has very specific rules and complex, new logic to get code to run. And I’m not yet talking about parallel execution of our blocks.
Another great advantage is its pluggable system of services. When we want to run a workflow, the Workflow Foundation can add services to extend its possibilities. One of the most interesting services already developed, is persistency. It gives us the possibility to have the workflow, its whole instance, being interrupted and saved on a data storage. This way, lengthy processes that are waiting on some user interaction can be cleared from main memory and brought back to execution only when needed!
All in all, Windows Workflow Foundation is quite a nice technology, which can be very powerful. Unfortunately, development is proofing to be quite challenging. This is why I decided to give this series a try to get things cleared up and help you guys with some hints and tips. Hope you’ll like the series. Stay tuned!
