Probems accessing Sharepoint 2007 services in WebParts using Silverlight?

Normally, for security, you do not want cross domain calls, but there’s times when you want to access an RSS feed or web service from another domain, and you are blocked from being able to do it (this is a good thing, it is saving accidents).

So if you fund you need to open things up a little, say you have a webpart n SharePoint which has Silverlight and it needs to call out somewhere, then you need to add a CrossDomain.xlm file or a ClientAccessPolicy.xml file to get things moving.

Here’s links to details on how to create a ClientAccessPoilicy.xml file and why you need it:

BTW Make sure you add the file(s) into SharePoint using the Microsoft Office Sharepoint Designer tool and not just physically copy the file in.