Make a Line the Focused element

[matthewcrews]

I am working on a problem where I need to create a onKeyPressed event for a line. For this to work I've been told that I need to make the element the focus for it to respond to events. I see how to make something "Focusable" but not how to focus on the element. Here is some example code:

Line.create [
    Line.startPoint (location * state.Zoom + state.WindowPosition)
    Line.endPoint state.PointerPosition
    Line.focusable true // Here I make the Line something I can focus on
    Line.stroke Dims.Line.color
    Line.strokeThickness 2.0
    Line.onKeyDown (fun e ->
        e.Handled <- true
        if e.Key = Key.Escape then
            Msg.Escape |> dispatch)
]

I also tried to create the line and then set a Focused property but I don't see one.

let line = Line.create [
    Line.startPoint (location * state.Zoom + state.WindowPosition)
    Line.endPoint state.PointerPosition
    Line.focusable true
    Line.stroke Dims.Line.color
    Line.strokeThickness 2.0
    Line.onKeyDown (fun e ->
        e.Handled <- true
        if e.Key = Key.Escape then
            Msg.Escape |> dispatch)
]
line.Focused <- true // This doesn't exist but it was my first thought
line

I'm also open to adding the onKeyDown handler to the Canvas element that I'm drawing the line one. That raises the same problem though. I asked a question on the AvaloniaUI GitHub which is what lead me to asking about setting the focus.

[JaggerJo]

IIRC not all controls can be in focus, they need to be IInputElements.

I would build my own way of knowing which line/box is selected.