Silverlight RIA Services applcation not binding data into comboboxes on some machines(!)

We have a very strange problem at the moment whereby our Silverlight 4 application will not display the contents of ComboBox on (some) client machines.

We have an observable collection in our view model, with a simple binding expression on the ItemsSource on the ComboBox. In the page's Loaded event, we are calling a domain service to retrieve the items, then in it's Completed event we are storing the r开发者_StackOverflow社区eturned items into the collection. Nothing fancy.

Firstly, when we deployed the solution in Release mode, the combobox's had no values. I opened fiddler and saw the request and response from the domain service, and it was in fact successfully returning the correct data to the client. However the combobox's had no data in them.

I rebuilt in Debug|Any CPU configuration, hit the same URL and it worked straight away - the combobox's were filled with data. Problem solved? Not quite.

We then gave the URL to someone else to test (on the same network/subnet) and the combobox s were empty again. It works on 5 machines, and doesn't work on the rest. I checked fiddler, and the response is coming back with all the data - Silverlight just doesn't populate the comboboxes.

We have tried a number of things - IE no addons, chrome incognito's, cross domain and client access policies... nothing seems to make a difference. We've tried running the browsers as administrator, we've even tried on very old machine running IE6, same issue (ie no UAC or anything strange there). No anti-virus installed on any of the machines. At a complete loss. We've tried machines on the company domain, and off the domain with no difference - different operating systems (xp/win7).

Does anyone have any ideas or solutions for me on this problem? Seems like there's something installed on the machine doing it?

Cheers,

Matt

This is probably a timing issue. ComboBoxes wreak all sorts of havoc. Check out Kyle's blog for tips and some tools to make things easier.

http://blogs.msdn.com/b/kylemc/archive/2010/11/02/silverlight-combobox-frequently-asked-questions.aspx

The general problem is that the Silverlight ComboBox was not designed with async data patterns in mind.