Jacobs Weblog

25 Jan 2007

Mono coding: Capturing right clicks in a Gtk.TreeView

I had a hard time figuring out how to capture a right click on a TreeView, which I needed to be able to make a context menu or popup menu or what ever you wanna call it. The way I expected it would work didn’t… I think it have something to do with a change in Mono some time ago (Why don’t I get ButtonPressEvents from my Button/Treeview?).

This example is based on the “Shortcuts – Writing Less Code” example from the www.mono-project.com website. The main difference is that the TreeView is no longer setup in the main class but is now a separate class with the function OnButtonPressEvent overwritten.

public class TreeViewExample {
    public static void Main ()
    {
        Gtk.Application.Init ();
        new TreeViewExample ();
        Gtk.Application.Run ();
    }

    public TreeViewExample ()
    {
        Gtk.Window window = new Gtk.Window ("TreeView Example");
        window.SetSizeRequest (500,200);

        MusicTreeView tree = new MusicTreeView ();
        window.Add (tree);
        window.ShowAll ();
    }
}

// Creating a new class MusicTreeView which is derived from the TreeView class
public class MusicTreeView : Gtk.TreeView {

        public MusicTreeView ()
        {
                Gtk.ListStore musicListStore = new Gtk.ListStore (typeof (string), typeof (string));

                this.AppendColumn ("Artist", new Gtk.CellRendererText (), "text", 0);
                this.AppendColumn ("Title", new Gtk.CellRendererText (), "text", 1);

                musicListStore.AppendValues ("Garbage", "Dog New Tricks");
                this.Model = musicListStore;
        }

        // The TreeView has a build in function which is called upon a OnButtonPressEvent
        // We override the function to capture right clicks with the mouse
        protected override bool OnButtonPressEvent (Gdk.EventButton evnt)
        {
                if(evnt.Button == 3) {
                        System.Console.WriteLine ("Right click");
                        return true;
                }
                // Now if we would ever get this far
                // we run the TreeViews OnButtonPressEvent function
                // to make sure everything else works as normal
                return base.OnButtonPressEvent(evnt);
        }
}

Update: I wrote a new “right click in Gtk.TreeView” example.

    // The TreeView has a build in function which is called upon a OnButtonPressEvent
    // We override the function to capture right clicks with the mouse
    protected override bool OnButtonPressEvent (Gdk.EventButton evnt)
    {

            if(evnt.Button == 3) {
                    TreeModel model;
                    TreeIter iter;
                    if (this.Selection.GetSelected (out model, out iter)) {
                        Console.WriteLine ("Selected row during right click" + model.GetValue (iter, 0).ToString ());
                    }               
                    return true;
            }
            return base.OnButtonPressEvent(evnt);
    }