How do I create a multi-level TreeView using F#?

Question

I would like to display a directory structure using Gtk# widgets through F#, but I'm having a hard time figuring out how to translate TreeViews into F#. Say I had a directory structure that looks like this:

Directory1
  SubDirectory1
  SubDirectory2
    SubSubDirectory1
  SubDirectory3
Directory2

How would I show this tree structure with Gtk# widgets using F#?

EDIT:

gradbot's was the answer I was hoping for with a couple of exceptions. If you use ListStore, you loose the ability to expand levels, if you instead use :

let musicListStore = new Gtk.TreeStore([|typeof<String>; typeof<String>|])

you get a layout with expandable levels. Doing this, however, breaks the calls to AppendValues so you have to add some clues for the compiler to figure out which overloaded method to use:

musicListStore.AppendValues (iter, [|"Fannypack" ; "Nu Nu (Yeah Yeah) (double j and haze radio edit)"|])

Note that the columns are explicitly passed as an array.

Finally, you can nest levels even further by using the ListIter returned by Append Values

let iter = musicListStore.AppendValues ("Dance")
let subiter = musicListStore.AppendValues (iter, [|"Fannypack" ; "Nu Nu (Yeah Yeah) (double j and haze radio edit)"|])
musicListStore.AppendValues (subiter, [|"Some Dude"; "Some Song"|]) |> ignore

Answer 1

I'm not exactly sure what you're looking for but here is a translated example from their tutorials. It may help you get started. Image taken from tutorial site.

I think the key to a multi-level tree view is to append values to values, iter in this line musicListStore.AppendValues (iter, "Fannypack", "Nu Nu (Yeah Yeah) (double j and haze radio edit)") |> ignore

// you will need to add these references gtk-sharp, gtk-sharp, glib-sharp 
// and set the projects running directory to 
// C:\Program Files (x86)\GtkSharp\2.12\bin\

module SOQuestion

open Gtk
open System

let main() =
    Gtk.Application.Init()

    // Create a Window
    let window = new Gtk.Window("TreeView Example")
    window.SetSizeRequest(500, 200)

    // Create our TreeView
    let tree = new Gtk.TreeView()
    // Add our tree to the window
    window.Add(tree)

    // Create a column for the artist name
    let artistColumn = new Gtk.TreeViewColumn()
    artistColumn.Title <- "Artist"

    // Create the text cell that will display the artist name
    let artistNameCell = new Gtk.CellRendererText()
    // Add the cell to the column
    artistColumn.PackStart(artistNameCell, true)

    // Create a column for the song title
    let songColumn = new Gtk.TreeViewColumn()
    songColumn.Title <- "Song Title"

    // Do the same for the song title column
    let songTitleCell = new Gtk.CellRendererText()
    songColumn.PackStart(songTitleCell, true)

    // Add the columns to the TreeView
    tree.AppendColumn(artistColumn) |> ignore
    tree.AppendColumn(songColumn) |> ignore

    // Tell the Cell Renderers which items in the model to display
    artistColumn.AddAttribute(artistNameCell, "text", 0)
    songColumn.AddAttribute(songTitleCell, "text", 1)

    let musicListStore = new Gtk.ListStore([|typeof<String>; typeof<String>|])

    let iter = musicListStore.AppendValues ("Dance")
    musicListStore.AppendValues (iter, "Fannypack", "Nu Nu (Yeah Yeah) (double j and haze radio edit)") |> ignore

    let iter = musicListStore.AppendValues ("Hip-hop")
    musicListStore.AppendValues (iter, "Nelly", "Country Grammer") |> ignore

    // Assign the model to the TreeView
    tree.Model <- musicListStore

    // Show the window and everything on it
    window.ShowAll()

    // add event handler so Gtk will exit
    window.DeleteEvent.Add(fun _ -> Gtk.Application.Quit())

    Gtk.Application.Run()

[<STAThread>]
main()