Question

I’ve started to look through WF and can’t catch how it can replace my Domain object functionality.
Here is simple Domain object scenario:

class Order {
    public int Id {get;}

    public OrderStatus Status {get;private set;}

    public void Approve () {
       if (Status >= OrderStatus.Approved)
          throw new InvalidOperationException("It is impossible to approve as order
          Status:" + Status);

       privateMethodCall();
       Status = Status.Approved;
    }

    public void Complete () {
       if (Status >= OrderStatus.Completed)
          throw new InvalidOperationException("It is impossible to Complete as order
          Status:" + Status);

       privateMethodCall1();
       Status = Status.Completed;
    }
}

I’ve read that WF can do it better as Approve and Complete code will be placed in one place
and it won’t be possible to call them in wrong order. Is it true? and if it is true can you show me how it will look in WF using object model (not xaml).

Thanks in advance.

Answer 1

There are 2 ways that you can use workflow:

• As a sequential process, in this case your sytem will move through the steps defined in the process and therefore things will not be called out of order.
• As a state machine, this would keep track of which state your order is in and what transitions are allowed. This is the one that most closely matches your code, see: http://blogs.msdn.com/b/endpoint/archive/2011/04/20/wf4-state-machine-user-experience.aspx

But, if you allready have code that works, I would not change it, you just add an extra layer of complexity without getting any business value.