ClickOnce and IsolatedStorage

Question

The Winform application is release with ClickOnce in our Intranet. We store personal preference for the GUI in the Isolated Storage. All works pretty fine :)

The problem is when we have a new version of the application, we publish... all preferences are lost! User need to setup their preference over and over each version.

Is there a way to freeze the isolation for the whole application instead of the version?

Answer 1

You have to store a permanent version of user settings in a more durable store like database. Your application can decide to use the isolated storage if it is available. If it is not available (because of a newer version), the app should get the settings from database and use it to re-initialize the settings in isolated storage. If settings are changed, you should update both places. Unless there is a newer version of the app, your app should not have to get the settings from DB.

Answer 2

I was working on a ClickOnce app a while ago and used Environment.GetFolderPath(ApplicationData) - e.g. roaming app data folder, to store all settings. Worked fine and survived numerous updates. Just create a subdireectory with the name of your app or CompanyName/AppName or whatever and store everything in there.

Answer 3

You need to use application scoped, rather than domain scoped, isolated storage. This can be done by using one of IsolatedStorageFileStream's overloaded constructors.

Example:

using System.IO;
using System.IO.IsolatedStorage;
...

IsolatedStorageFile appScope = IsolatedStorageFile.GetUserStoreForApplication();    
using(IsolatedStorageFileStream fs = new IsolatedStorageFileStream("data.dat", FileMode.OpenOrCreate, appScope))
{
...

However, now you will run into the issue of this code only working when the application has been launched via ClickOnce because that's the only time application scoped isolated storage is available. If you don't launch via ClickOnce (such as through Visual Studio), GetUserStoreForApplication() will throw an exception.

The way around this problem is to make sure AppDomain.CurrentDomain.ActivationContext is not null before trying to use application scoped isolated storage.