How to make application settings independent of .exe path?

Question

Suppose I want to move my app from c:\myapp.exe to d:\myapp.exe. It will loose all settings. How to prevent that?

Answer 1

Personally I use the registry to save and load my settings, so the location of my application isn't affected, but if you're using User.Config etc and want to fix the location, this might help: Can I control the location of .NET user settings to avoid losing settings on application upgrade?

Answer 2

It is an implementation detail of the LocalFileSettingsProvider class. Which has the unenviable job of storing user-scoped settings in a file that's guaranteed to be unique so that different apps cannot accidentally overwrite each others settings.

It does so by storing the file in an AppData directory that has a hashed name. The hash is computed from several properties of the application. It grabs as much as it can, starting with the attributes in the AssemblyInfo.cs file. Particularly the [AssemblyVersion] matters which is how it can detect that a new version of your app might not be compatible with the old version of the user.config file.

But the attributes are not enough to make it unique, it also uses the full path name of the .exe in the hash. Which is a very strong selector for the appropriate .config file.

So, inevitably, if you move the .exe somewhere else, that's going to change the hash and that's going to get you an empty user.config file with all the settings back to their default setting.

It's a bit questionable to tinker with this, an app should only ever have one install directory. c:\program files\companyname\appname is the standard. But you can by implementing your own SettingsProvider class. That's not exactly easy to do, System.Configuration is a pretty nasty namespace. But a decent starting point is the RegistrySettingsProvider sample, which is probably usable as-is.

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