Can two Silverlight applications share IsolatedStorage on one machine?

Question

What identifies an silverlight application and when can two silverlight applications share IsolatedStorage if at all, i.e.:

• if I want to have two Silverlight applications share IsolatedStorage space, is this possible? What kind of "application id" do I need to give to do this?
• if I don't want two Silverlight applications to share IsolatedStorage, how do I prevent this? Do I need to do this?

For instance, I've noticed when I develop a Silverlight application, I can press F5, in the application save to Isolated Storage, stop the application, press F5 again, and it reads from the same IsolatedStorage. (I would think that a new compilation would cause it to use new IsolatedStorage.)

However, when I then copy the .xap and .html files to another directory and open the .html file, it does NOT share the IsolatedStorage with the application I was developing. What changed?

What is going on behind the scenes here so I know when IsolatedStorage is shared and when it isn't?

Answer 1

The URL to the source XAP file identifies the application. You would want a new version of an application to be able to read the existing store for a previous version. Consider a game where all the high scores are stored in the application store. The user might be a little upset when all those scores disappear after they upgraded it.

Different applications can share a single site based store. However you only get those two levels of granularity, app level keyed at the XAP Url or site based, which is host and port (I'm not sure whether scheme is also part of that key).

Answer 2

If memory serves me right the isolated storage can be used within the scope of the application and scope of the page. So - if I understand my recollection right, I'd probably say - yes.

Edit

From a copy of Pro Silverlight 3.0 in C# that I posess :

(p. 636) With isloated storage, a niqe storage location is created for every combination of user and application. In other words, the same computer can have multiple isloated storage locations for the same application, assymin each one is for a different user. Similarly the same user can have multiple storage locations one for each Silverlight Application

(p. 637) ... GetUserStoreForFile(). This method provides a storage site that's accessible to all silverlight applications on the same website domain, however these settings are still user specific