.NET Configuration (app.config/web.config/settings.settings)

Any configuration that might differ across environments should be stored at the machine level, not the application level. (More info on configuration levels.)

These are the kinds of configuration elements that I typically store at the machine level:

• Application settings
• Connection strings
• retail=true
• Smtp settings
• Health monitoring
• Hosting environment
• Machine key

When each environment (developer, integration, test, stage, live) has its own unique settings in the c:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG directory, then you can promote your application code between environments without any post-build modifications.

And obviously, the contents of the machine-level CONFIG directory get version-controlled in a different repository or a different folder structure from your app. You can make your .config files more source-control friendly through intelligent use of configSource.

I've been doing this for 7 years, on ov

We used to use Web Deployment projects but have since migrated to NAnt. Instead of branching and copying different setting files we currently embed the configuration values directly in the build script and inject them into our config files via xmlpoke tasks:

  <xmlpoke
    file="${stagingTarget}/web.config"
    xpath="/configuration/system.web/compilation/@debug"
    value="true"
  />

In either case, your config files can have whatever developer values you want and they'll work fine from within your dev environment without breaking your production systems. We've found that developers are less likely to arbitrarily change the build script variables when testing things out, so accidental misconfigurations have been rarer than with other techniques we've tried, though it's still necessary to add each var early in the process so that the dev value doesn't get pushed to prod by default.

Like you I've also set up 'multi' app.config - eg app.configDEV, app.configTEST, app.config.LOCAL. I see some of the excellent alternatives suggested, but if you like the way it works for you, I'd add the following:

I have a
<appSettings>
<add key = "Env" value = "[Local] "/> for each app I add this to the UI in the titlebar: from ConfigurationManager.AppSettings.Get("Env");

I just rename the config to the one I'm targetting (I have a project with 8 apps with lots of database/wcf config against 4 evenioments). To deploy with clickonce into each I change 4 seetings in the project and go. (this I'd love to automate)

My only gotcha is to remember to 'clean all' after a change, as the old config is 'stuck' after a manual rename. (Which I think WILL fix you setting.setting issue).

I find this works really well (one day I'll get time to look at MSBuild/NAnt)