Yesterday I walked into an interesting problem. After I finished cleaning up an SVN debug folder, my MVC app stop working, specifically calls to JSON. That were working previously.
I thought it must have something to do with silverlight since it was there where I found the exception. I did a series of searches looking for an answer, but I didn't find one since I looking at the wrong thing.
The actual problem had to do with MVC. I was getting the following response:
This request has been blocked because sensitive information could be disclosed to third party web sites when this is used in a GET request. To allow GET requests, set JsonRequestBehavior to AllowGet.
I did a search on this error. Behold! The issue was a change in how JSON is handled in .NET MVC. Adding a simple line took care of the issue.
return Json(result, JsonRequestBehavior.AllowGet);