Comments on: Silverlight Duplex Services

By: Jones sabo this mixture attracts critical diversif

Jones sabo this mixture attracts critical diversif — Sat, 20 Apr 2013 12:23:45 +0000

Its wonderful as your other articles : D, regards for posting . “The art of love … is largely the art of persistence.” by Albert Ellis

By: Eliezer

Eliezer — Wed, 09 Sep 2009 12:20:03 +0000

Speak is easy, hard is to do. To use WCF to notify clientes is really confusing and hard and how WCF usually is asynchronous you never know if user changed the interface (made a new query for example) that WCF return isn’t necessary. I’m trying tell you that there is another ways but COMET is a more easy to implement, to maintainence and to understand.

I see a lot of people talking about “Another ways to get real-time clientes” but nobody don’t post any piece of code

By: james peckham

james peckham — Mon, 10 Aug 2009 00:42:26 +0000

Do you have any examples of doing true push behavior in silverlight?

By: tgreenfield

tgreenfield — Sat, 08 Nov 2008 19:51:20 +0000

Good question Robert, When the request comes in to update the database, you could first write to the DB and then just broadcast that change back out to the other clients right from your web service that handled the request. Note: you would need to store all the client connection sessions in a shared variable or the Session object. That way your request handler would have access to them.
You would need to ensure that any changes to your database would need to go thru this single web service or they’d be missed. Of course it might be good practice anyway to restrict the db updates to a single gateway.
Another way if you’re using MS SQL (which I haven’t tried yet) is to create a trigger that calls out to a web service to broadcast the changes out to all connected clients.

By: Robert S

Robert S — Fri, 07 Nov 2008 02:28:25 +0000

tgreenfield,
I agree with this and am trying to implement it in a web application. But it is not clear to me how the server end of the duplex service can monitor the database. For instance, if there are 5 users connected to the app, and one of them creates a new “Product” which gets published to the database, this would mean that the server end of the app would have to monitor the database for any updates/changes to push out to the other 4 clients. Or am I thinking incorrectly here? The only other option I could see would be to have the server end of the duplex service register the updated “Product” independently of the database update, and just push it out to the other 4 clients as it is updated. Basically, what I am wondering overall is: Is it possible for the server end of the duplex service to have real time monitoring of the database changes, or does this need to be handled separately?