I tried the repro scenario with an app of mine and confirmed what I expected, that IsolatedStorageSettings.ApplicationSettings.Count
was nonzero on entry to the App() ctor upon running the app for a second time in the same emulator process. So there is hope for you to get to this desired state too!
Since you report that the _ApplicationSettings file is not empty, I'll guess 2 possibilities: Maybe an app (or some other process?) keeps the _ApplicationSettings file open when the 2nd run of the app is trying to open the file for reading? MSFT doesn't document how the read is done, so maybe the file is opened with FileShare.None, or with FileShare.Read but some other process still has the file open for writing? I have no idea how to test this on the emulator, but on the real device you might try this scenario:
- Run the app for the first time, verify it saves a non-empty _ApplicationSettings.
- Restart the phone device (debugger will disconnect)
- Run the app for the second time, with a breakpoint in App() ctor.
After 2) I would be confident no other process could have the file open, so the app should be able to read its contents without interference. But if you discover that it still has zero count in 3), then another possibility exists:
Maybe the restarted app encounters an error trying to deserialize the settings from the file into your data structure(s)? The error might not prevent the data from being serialized when the first run of the app is exiting.
To check this possibility, first look for error messages in the Output, Debug window. Do you see any errors when restarting the app the a second time?
If you don't see any helpful error messages, the next thing to try is to simplify the data structures being saved as settings. Try cutting down to just one setting that is a simple type like an int or string. See whether that can be restored correctly, then add more of your settings back into the file until you home in on the one which causes a problem.