I wouldn't to anything to move to next segment since this features are already available in Studio with shortcuts and people are already used with them. The way I would implement your feature is something like this:

1. Create the viewpart which displays the unicode characters

2. When segment is changed automatically load the text in your editor. You can be notified by this event.

3. Add a button that will replace the text from your editor in the segment that can be used by the user. Also provide a shortcut for it since this can become handy for users.

This way this is very easy for the user to user their current way of working but also take advantage by your feature.

Hi Romulus,

I tried to listen ActiveSegmentChanged but seems failed, can you help?

this is code:

[ViewPartLayout(typeof(EditorController), Dock = DockType.Bottom)]
    class MongolianEditorController : AbstractViewPartController
    {
        protected override System.Windows.Forms.Control GetContentControl()
        {
            return _control.Value;
        }
        protected override void Initialize()
        {
            editorController = SdlTradosStudio.Application.GetController<EditorController>();
            _document = editorController.ActiveDocument;
            _document.ActiveSegmentChanged += new EventHandler(_document_ActiveSegmentChanged);
        }
        private void _document_ActiveSegmentChanged(object sender, EventArgs e)
        {
            _control.Value.textBox1.Text = _document.Selection.Target.ToString();
        }
        private Document _document;
        private EditorController editorController;
        private readonly Lazy<MongolianEditer> _control = new Lazy<MongolianEditer>(() => new MongolianEditer());
    }

I don't understand why readonly Lazy<MongolianEditer> _control, is this cause failed interactive with control?

Does that means actions should be inside control but not the controller, a little confused.

The control is created using Lazy<T> as a small optimization to postpone the creation of the actual control until is actually needed. When Studio starts it will load all ViewPartControllers including the ones from the plugins which in your case means that an instance of MongolianEditorController will be created when Studio is starting. The problem is that the user might not open the editor view which means that your view part will never be displayed. If we don't use Lazy<T> your user control will be created when Studio starts but it might not be used. Hope this make sense :).

Regarding your problem have you try to set a break-point inside _document_ActiveSegmentChanged and see if is hit? Also you trying to get the target text from the selection property which will always be empty in this event. Selection property represents the text that you select with the mouse cursor inside a segment which will always be empty when you change segments. To get the text from the target segment you can do something like this _document.Target.ToString().

If you are interested to react when a text is selected you should used the Change event from the _document.Selection.