How to update the "disabled" property in a custom widget?

roinr · January 11, 2021, 9:23pm

I’ve create a custom widget and I’m trying to set its “disabled” property in a callback function:

ms = CustomMultiSelect(value=["a"], options=["a", "b"])


def callback(attr, old, new):
    ms.disabled = True


ms.on_change('value', callback)

curdoc().add_root(ms)

When the callback is invoked I get the following error in the console:

Seems like it happens only when trying to set the “disabled” property. Other properties don’t cause this error.

Bryan · January 11, 2021, 9:28pm

Best guess: you would need to implement the abstract controls method on your custom widget view to return all fo the HTML elements that need to have their disabled property updated. See:

github.com

bokeh/bokeh/blob/f91a3a668ea3ee39e02eee2fc46bba759b8395ab/bokehjs/src/lib/models/widgets/control.ts

import {Widget, WidgetView} from "./widget"
import {toggle_attribute} from "core/dom"
import * as p from "core/properties"

export abstract class ControlView extends WidgetView {
  model: Control

  abstract controls(): Iterable<HTMLElement & {disabled: boolean}>

  connect_signals(): void {
    super.connect_signals()

    const p = this.model.properties
    this.on_change(p.disabled, () => {
      for (const el of this.controls()) {
        toggle_attribute(el, "disabled", this.model.disabled)
      }
    })
  }
}

This file has been truncated. show original

If that’s not it, then you would need to provide actual code to investigate in order to speculate further.

Also, I should remind that it is always advised to include relevant version information in all questions.

roinr · January 12, 2021, 10:51am

Thanks @Bryan!
It didn’t work for me (maybe I did it wrong since I’m not so familiar with BokehJS).

I ended up creating a new enabled property for the widget so I’ll use it instead. I figured it will be the easiest/fastest sufficient solution.

Also, I should remind that it is always advised to include relevant version information in all questions.

Right, sorry for that.