Callbacks and events

Generated callback properties

Every public RevoGrid event discovered in Stencil compiler metadata is generated as a same-name Dash input property. The most common events are active by default:

Dash property	When it updates	Typical detail	Core reference
afteredit	A cell or selected range is changed	Compact cell delta, or range data and ranges	AfterEditEvent
afterfocus	Focus rendering completes	Focused cell/range information	FocusAfterRenderEvent
headerclick	A column header is clicked	JSON-safe column definition	ColumnRegular
roworderchanged	A row reorder is requested	from, to	Row Drag and Drop
aftersortingapply	Sorting finishes	Final sorting state and affected row types	AfterSortingApplyEvent
beforefilterapply	Filtering is about to apply	Filter collection	Filtering events
aftercolumnresize	Column resizing finishes	Resized columns keyed by index	Column Resize

All callback values use the same envelope:

{
  "name": "afteredit",
  "detail": {
    "rowIndex": 0,
    "colIndex": 2,
    "prop": "amount",
    "val": 140,
    "type": "rgRow",
    "colType": "rgCol"
  },
  "timestamp": 1784980000000,
  "sequence": 1
}

• name is the lowercase RevoGrid DOM event name.
• detail contains the JSON-safe event payload.
• timestamp is the browser time in Unix milliseconds.
• sequence increases for every emitted bridge event, so two identical consecutive event payloads still trigger Dash.

For a single-cell edit, afteredit.detail keeps only rowIndex, colIndex, prop, val or value, type, and colType. For a range edit, it keeps data, newRange, oldRange, and type. Grid-owned models and collections are intentionally removed.

Observe several events

from dash import Input, Output, callback, ctx
import json


@callback(
    Output("grid-events", "children"),
    Input("orders-grid", "afteredit"),
    Input("orders-grid", "afterfocus"),
    Input("orders-grid", "aftersortingapply"),
    prevent_initial_call=True,
)
def show_grid_event(afteredit, afterfocus, aftersorting):
    property_name = ctx.triggered[0]["prop_id"].rsplit(".", 1)[1]
    event = {
        "afteredit": afteredit,
        "afterfocus": afterfocus,
        "aftersortingapply": aftersorting,
    }[property_name]
    return json.dumps(event, indent=2)

For callbacks with several inputs, dash.ctx identifies exactly which property triggered the callback.

Subscribe to any other RevoGrid event

Use eventListeners to activate generated event properties that are not active by default. Their latest payload is published through both the same-name property and the backwards-compatible eventData property:

grid = RevoGrid(
    id="orders-grid",
    eventListeners=[
        "aftergridinit",
        "filterconfigchanged",
        "sortingconfigchanged",
    ],
    columns=columns,
    source=rows,
    style={"height": 420},
)


@callback(
    Output("generic-event", "children"),
    Input("orders-grid", "eventData"),
    prevent_initial_call=True,
)
def show_generic_event(event):
    return f'{event["sequence"]}: {event["name"]}'

Names are deduplicated and listeners are updated when eventListeners changes. Default event names do not need to be listed because their generated Dash properties already receive them. Runtime plugin events absent from Stencil metadata continue to update eventData only.

Do not subscribe to high-frequency events such as viewportscroll unless a server round trip for every event is intentional.

Browse the complete Core events table and event lifecycle guide to choose names and understand event order.

JSON-safe event serialization

The bridge serializes event details before calling Dash setProps:

• strings, finite numbers, booleans, null, arrays, and plain objects remain;
• JavaScript Date values become ISO strings;
• non-finite numbers, cycles, DOM nodes, and class instances become null;
• unsupported object fields such as functions, symbols, and undefined are omitted;
• unsupported array entries become null.

This protects callbacks from DOM and grid-internal objects that Dash cannot transport.