What's New in Windows Workflow Foundation in .NET 4.5 (part 2)
During the last //build/ conference a number of new WF4.5 features where announced. In part 1 I took a look at the designer improvements, in this blog post I am going to take a look at some of the runtime enhancements.
New activities.
As part of WF 4.5 we will see some new activities in the box. The number isn’t earth shattering but as I always tell people WF activities are all about your business and Microsoft can’t create activities tailored to your business, you need to do so yourself.
One useful new activity is the NoPersistScope. Not that it is very hard to create yourself once you know how, I wrote a blog post about it here, but not easy to discover and certainly something that is very useful.
State machine
Although not completely new, it was released as part of the .NET 4 platform update 1, the state machine is now rolled into the .NET framework proper so it doesn’t require an additional install. Nice to see that back 
C# Expressions
One thing a lot of developers are going to be very happy with is support for C# expressions. Previously you where forced to use VB expressions, even in a C# project. And while that isn’t extremely hard it did require a mental switch and, as most C# developers aren’t fluent in VB, some frequent searching for the right syntax. With WF 4.5 you can enter you expressions using the C# syntax in a C# project and in VB syntax in a VB project. So much better
Besides C# expression it appears we can also replace the expression authoring experience with something we control using new extensibility points in the designer. So far I have not seen any details of this so I am curious to what kind of scenarios this opens up.
Versioning
The most important new feature is workflow versioning. The next blog post I will go into details on what this new feature brings us.
Enjoy!
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