Ahmed Nagy

I've been trying lately to customize some WWF components and activities to fit my needs. In many cases I find that most nice classes are sealed!!

For example, say you want to customize the PolicyActivity to add some new property or even simpler change its appearance. You have to find another way to do that, because you cannot inherit, such class is sealed!!! 

Also many helper classes are internal and the some good functions that might help customizing are marked internal. As an example, the good looking curved connectors in the state machine diagram, they are marked as internal. So, when I was trying to extend some sample to create (Flow chart) workflow type, I was stucked.

Now all this is put constraints to the extensibility of the WWF and make developers life harder when trying to extend already existing object model in WWF.

Any one can give thoughts for why such design decision was taken Any thoughts I'm just trying to share thoughts and experience




Re: Windows Workflow Foundation Windows Workflow Foundation design and some limitations

Sung Hon Wu

Hi,

What exactly is your scenario Maybe we can help. Have you looked at some policy examples

Like, http://wf.netfx3.com/files/folders/rules_samples/entry8850.aspx . Its not the builtin policy activity but much of the same thing.






Re: Windows Workflow Foundation Windows Workflow Foundation design and some limitations

Kavita Kamani - MSFT

Hi

Your feedback is well taken. You have to understand that every extensibility point has to be tested before release. As a result, for V1, we decided to keep some stuff as sealed, yet provide enough extensibility for you to write your custom activities.

As Sung Hon says, if you have specific scenarios that just cannot be implemented on the platform or are really hard to implement, that's good feedback to share with us as we plan and work towards our next update. This kind of feedback is much appreciated and is definitely passed on to the product team.

Thanks,

Kavita






Re: Windows Workflow Foundation Windows Workflow Foundation design and some limitations

Netsrac

Full Ack!!

The sealed classes are definitely a big problem at the current release.
I know that the workflow designer was build for developers and not for end users.
But there are several "end user scenarios" which were impossible or very hard (due to missing documentation) to implement.
Here are some scenarios for state machine workflows:

  • Show the end user a "simplified" version of a state machine workflow
    E.g.: when dealing with workflow in a document management system (dms) the user is only interested in the current state of the document and does not want to see the EventHandlers of the StateActivities.
  • The endpoint of a node connector in a state machine is always at the top or bottom of the StateActivity.
    With a complex Workflow (>10 states) it is very hard to arrange the states in a comprehensible way.
    Why can't I connect the states at the left or right site
  • How to add Windows Forms Controls to Activites
    As an end user, I want to change the current state by clicking at a "Change status" button at the current StateActivity.
  • How to show the transitions between states as "boxes" at the state machine workflow
    As an administrator, I want to see why a transition is not completet yet (e.g. because of a missing vote from a user)


For building "real world" applications with the Windows Workflow Foundation there are missing a lot of features and there are many unnecessary hurdles for developers at the moment.

netsrac





Re: Windows Workflow Foundation Windows Workflow Foundation design and some limitations

Kavita Kamani - MSFT

Hi Netsrac

Again, I'd like to thank you for the feedback. We believe we made progress in our V1 product by trying to enable scenarios that were not possible before or were hard to implement. But, its a V1 product and we couldnt get all we liked.

I can tell you we're seriously looking into enabling easy authoring of custom activities, a broader set of out of box activities, not sealing our activities etc - for our next version. You have some good feedback on the state machine workflow designer that I will make sure to pass on to the right PM.

Thanks again and keep the feedback coming so we can deliver to you guys what you want to see.

Kavita






Re: Windows Workflow Foundation Windows Workflow Foundation design and some limitations

Ahmed Nagy

Hi Kavita;

Mentioning State Machine workflows, we had another big limitation and that was about events....

- You can only have on Event driven activity at any state

- That event driven activity must be the first in the state

I'd like to mention that WWF is great even with those limitations. You guys have done a great job.






Re: Windows Workflow Foundation Windows Workflow Foundation design and some limitations

Kavita Kamani - MSFT

Yes, I've passed along the feedback and we'll open a bug in our internal database with the feedback.