While F# is a first-class .NET 4 citizen it’s not really a first-class Visual Studio citizen, even in 2010. A lot of the application setup tools we have for C# aren’t present in F#.

I was recently making a quick and dirty tool in F# that needed some basic user settings, so I went with the ApplicationSettings infrastructure in .NET, as it’s the easiest way to implement this. In C# this is easy, the GUI designer writes the code for you. In F# you have to do it yourself. Microsoft’s documentation is in C#, so there’s some adaptation to do.

You’ll need a type that inherits ApplicationSettingsBase class from System.Configuration, and then add some property members with the attribute UserScopedSettingAttribute(). You can also use ApplicationScopedSettingAttribute() for application-level settings, but these require editing the XML in your App.Config, something that I’m not that familiar with yet.

There’s a little boilerplate for each setting, but other than that it’s a breeze.

Here’s a sample settings class:

    open System.Configuration
    type MySettings() = 
      inherit ApplicationSettingsBase()
      member this.UserSetting
        with get() = this.Item("UserSetting") :?> string
        and set(value : string) = this.Item("UserSetting") <- value
      member this.AppSetting
        with get() = this.Item("AppSetting") :?> string