Skip to main content

Workflows and MS WF

Yesterday, I completed my training on Windows Workflow foundation.
In my opinion, it yet a new tech and provides you with a set of good features.
However, a question that was racing my mind all the time was, why the hell do you need workflows, I mean almost all programs that we write have activities and business logic within them, so what the big use of using a framework to model workflows.

These were some of the pointers the trainer think of if you need to go for workflows.

1) Activities can be clearly identified with boundaries
2) Whether to use state machine workflows can be determined if the logic is push based and not pull based
3) When rules need to be customized externally without rebuilding the system.
4) You have huge number of human interaction (to determine if you need to use state machines)
5) Long running process that can be done asynchronously without user intervention

On the other hand, MS Workflow foundation has its own advantages.
1) A cool designer support.
2) Custom activities can be created that is compiled but you can have your work flow in an external XML file, so it s configurable. The workflows loaded into the runtime by de-serelizing the XML and passing the XML reader into the CreateWorkFlow method of the runtime.
3) Workflows can be started and stopped at will, and the program state can be persisted (the property values and all), there is a default persistence service you can use with SQL server.
4) Transaction handling is cool, putting up a transaction scope would revert back the whole set of state of the workflows (even reseting member variables that we changed in the process).
5) For the stuff that the workflow cannot revert back in a transaction rollback, you can write your compensation transaction.
6) Fault handling can be done for each activity of the work flow.
7) You can host the runtime in a asmx webservice or a wcf sebservice, how you do this is also becomes simple.


We'll these are some of this stuff I remember and by the way state machine gets deprecated in .net 4.0

Comments

Popular posts from this blog

Hosting WCF services on IIS or Windows Services?

There came one of those questions from the client whether to use II7 hosting or windows service hosting for WCF services. I tried recollecting a few points and thought of writing it down. WCF applications can be hosted in 2 main ways - In a Windows service - On IIS 7 and above When WCF was first released, IIS 6 did not support hosting WCF applications that support Non-HTTP communication like Net.TCP or Net.MSMQ and developers had to rely on hosting these services on Windows Services. With the release of IIS 7, it was possible to deploy these Non-Http based applications also on IIS 7. Following are the benefits of using IIS 7 to host WCF applications Less development effort Hosting on Windows service, mandates the creating of a Windows service installer project on windows service and writing code to instantiate the service, whereas the service could just be hosted on IIS by creating an application on IIS, no further development is needed, just the service implementa

The maximum nametable character count quota (16384) has been exceeded

Some of our services were growing and the other day it hit the quote, I could not update the service references, nor was I able to run the WCFTest client. An error is diplayed saying " The maximum nametable character count quota (16384) has been exceeded " The problem was with the mex endpoint, where the XML that was sent was too much for the client to handle, this can be fixed by do the following. Just paste the lines below within the configuration section of the devenve.exe.config and the svcutil.exe.config files found at the locations C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE , C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin Restart IIS and you are done. The detailed error that you get is the following : Error: Cannot obtain Metadata from net.tcp://localhost:8731/ Services/SecurityManager/mex If this is a Windows (R) Communication Foundation service to which you have access, please check that you have enabled metadata publishing at the specified address. F

ASP.NEt 2.0 Viewstate and good practices

View state is one of the most important features of ASP.NET because it enables stateful programming over a stateless protocol such as HTTP. Used without strict criteria, though, the view state can easily become a burden for pages. Since view state is packed with the page, it increases size of HTTP response and request. Fortunately the overall size of the __VIEWSTATE hidden field (in ASP.NET 2.0) in most cases is as small as half the size of the corresponding field in ASP.NET 1.x. The content of the _VIEWSTATE field (in client side) represent the state of the page when it was last processed on the server. Although sent to the client, the view state doesn't contain any information that should be consumed by the client. In ASP.NET 1.x, if you disable view state of controls, some of them are unable to raise events hence control become unusable. When we bind data to a grid, server encodes and put whole grid in to view state, which will increase size of view state (proportional to the