where property.setting value stored in c# windows application

Question

I thought it should be a config file, but cannot find it. thanks

Answer 1

The whole config file location can be a bit slippery. Depending on whether or not its a "user" setting or an "application" setting, it will go into a different file. Some settings can even come from your "machine" config (Like in the case of ASP.NET). Instead of guessing where everything is, I find it much more useful to ask .NET where it is looking for these files. Roughly:

//Machine Configuration Path
string path1 = ConfigurationManager.OpenMachineConfiguration().FilePath;
//Application Configuration Path
string path2 = ConfigurationManager.OpenExeConfiguration( 
      ConfigurationUserLevel.None).FilePath;
//User Configuration Path 
string path3 = ConfigurationManager.OpenExeConfiguration(
      ConfigurationUserLevel.PerUserRoamingAndLocal).FilePath;

App.Config

This is what gets added to your project. The build process will name it [myproject].exe.config. This holds the (mostly) read only application settings and the application-level defaults for user-specific settings. Application level settings are difficult to programmatically change their values. Application level setting properties will only have "get" defined. The intention is: if your setting is for all users of the application, then a manual edit (or the installer) should set them. If it changes per user, then make it a per-user setting.

Binary Default Settings

Your application will run without its [myproject].exe.config file. To do this, the binary has its own version of the file "stored". This is useful in some ways, but can be confusing. If you have a .config file in the wrong place or with the wrong name, .NET reverts to the "binary defaults". It can cause the appearance of not being able to affect the settings by changing the config file. Use the method above to know where the .config REALLY goes, or face the wrath of the binary default settings.

User.Config

This is generated the first time you "save" your Default.Settings object with a "per-user" setting. This file is saved in the user's profile path in a location based on your project's name, version, operating system, and some other dark .NET magics. The properties for these settings are readable/writeable. They are designed to be easily set and then saved with a single call.

Pulling it Together

So where do my settings go? The answer is that potentially many files are joined together to get the "Active set" of settings. App.config and user.config settings are the basic blocks, but there are machine.config settings, and then there are dependency assembly settings that can further complicate things...but thats another topic entirely.

The real truth of config files is spread across a lot of ugly cases and details. However, with a little knowledge about how they are joined together, it is a fairly useful system. Especially if you realize you can databind to these settings ;)