When to Use Which Workflow Type in C#.NET

Creation ECC200 in C#.NET When to Use Which Workflow Type

Sequential workflow within WF follows the traditional thinking of workflow. That is, the workflow is in control. As long as the process is simple and rarely goes outside the bounds, then a Sequential workflow will work. For example, an employee performance review workflow might have an employee s supervisor create a review and send the review to the employee. The employee sends the review back to the supervisor, and the supervisor sends the review to the employee. The supervisor is involved twice, but there s little room for deviation from the flow. This is a good example of a Sequential workflow. Again, remember that just because the flow is sequential doesn t mean it can t have branching and looping. On the other hand, State Machine workflow deals with different states. A process that can have many different iterations is a candidate for a State Machine workflow. A help desk system would be a good candidate for a State Machine workflow. For example, a user creates a ticket and that ticket goes into a queue. The state of the ticket is pending. The help desk manager reviews the queue and sets a priority. Also, the help desk manager then assigns the ticket to a technician. The state of the ticket is now assigned. The technician says to begin work on the ticket. The state is now Working. However, the technician must wait for information from another vendor. The state goes to pending vendor. After some time, the vendor returns information. However, the technician doesn t have time to work on the ticket, so he assigns it to another technician. The state is back to assigned. The technician begins and completes the work and the ticket is closed. The state is now closed. Performing this type of process with a Sequential workflow would require a lot of while loops and if branching, because there are so many possible statuses and not every ticket would use each state. Most tickets wouldn t use the pending vendor status, but some tickets might.

Why might you even want to use workflows I can, and have, created a help desk application with the same complexities mentioned earlier as an ASP.NET application with Visual Basic. The biggest reason to create workflow, especially with WF, is that you re creating a model. Most projects that facilitate a business process have some type of model associated with them. This model might be use cases and UML diagrams, or it might be as simple as a flow chart. These are models ways to look at the process. With WF, the model and the workflow are the same thing. You use pieces of the business process to make a workflow, and you piece together the business process, which makes a model. Before WF, you d create UML diagrams that showed how classes were to interact, and with some tools you could get the diagrams to create class definitions automatically, along with method and property definitions. With WF, when you re laying out the business process that is, modeling the business process you re also building the application. WF also has other facilities that help take care of a great deal of the plumbing related to workflow. For example, you can persist workflow data, so that even during a reboot, running processes can be started from the point they stopped. Finally, WF allows processes to change on the fly. You can change the process while instances of the process are running, and the instances will adhere to the new process.

Windows Workflow Foundation (WF) is a technology that Microsoft has packaged with the .NET Framework for Microsoft Vista. WF is part of the programming model for Microsoft Vista, the next release of the Windows operating system. The new name for that programming model is WinFX, and it s a significant expansion of the Microsoft .NET Framework that was first released several years ago. Although WF is part of the WinFX programming model for Windows Vista, it can be run on clients that have Windows Server 2003 SP1, Windows XP SP2, Windows XP Home Edition, or Windows XP Media Center Edition. To develop workflow applications, you must be using Visual Studio 2005 any version except Express. You can build workflow applications using VS2005 by adding the Visual Studio 2005 Extensions for Windows Workflow Foundation.