# Dropdown

Pick one option from a list you define or bind to data.

## Add it to an app

1. Open the app builder and find **Dropdown** in the component palette.
2. Insert it into the intended region or container.
3. Set its properties in the inspector. Use a literal for a fixed value or a binding for a value supplied by the app.
4. Connect its events where the app should respond to a user gesture.
5. Preview with representative data and save after resolving validation problems.

The type name in the builder’s code view is `select`.

## Settings

| Setting | Accepted value | Required | Default | What it controls |
| --- | --- | --- | --- | --- |
| Label (`label`) | string | No | "Select" | Supports expression bindings. Shown above the control; also its accessible name. The listed default is inserted when adding a new component. |
| Options (`options`) | list of value | No | [] | Supports expression bindings. Strings, or { value, label } objects. The listed default is inserted when adding a new component. |

## Values available to bindings

| Value | Type | Initial value | Meaning |
| --- | --- | --- | --- |
| `value` | string | "" | The chosen option's value. |

Refer to these values through `components.<component-id>.<value>` in a binding. Use the identifier assigned to this instance of Dropdown, not the component type name.

## Events

- `onChange` — An option was picked, after `value` is published.

Connect only the actions the app needs. An event can fetch results, run an enabled data source, set state, update another component, show a notification, or navigate where supported.

## Keyboard and accessible labels

Accessible label source: `label`, else 'Select'.

- Arrow keys change the option.

## Example: Static options

| Setting | Example value |
| --- | --- |
| `label` | "Category" |
| `options` | [{"label":"All categories","value":""},{"label":"Bug","value":"bug"},"question"] |

## Example: Bound options feeding app state

| Setting | Example value |
| --- | --- |
| `label` | "Topic" |
| `options` | "{{ app.topics }}" |

When `onChange` occurs, the example performs:

- `setStateValue` with {"key":"topic","value":"{{ components.Topic.value }}"}

## If it is empty or unavailable

Check the source binding, the selected item, and the app’s access. A hosted document, table, review, or storage component needs the corresponding app capability; an offline preview cannot supply live private data. A source running with no results is different from an invalid binding. Inspect the app’s workflow and data source before changing the presentation.