---
url: /docs/9.x/guide/form-fields/select.md
---
# Select

Class: `Code16\Sharp\Form\Fields\SharpFormSelectField`

## Configuration

### `self::make(string $key, array $options)`

The `$options` array can be either:

* a simple key-value array
* an array of arrays with `id` and `label` keys. Fore instance:

```php
[
    ['id'=>1, 'label'=>'Label 1'],
    ['id'=>2, 'label'=>'Label 2'],
]
```

This allows to write code like this:

```php
SharpFormSelectField::make(
    'travel_id',
    Travel::orderBy('departure_date')
        ->get()
        ->map(function ($travel) {
            return [
                'id' => $travel->id,
                'label' => $travel->departure_date->format('Y-m-d') 
                    . ' — ' . $travel->destination
            ];
        })
        ->all()
);
```

### `setMultiple(bool $multiple = true)`

Allow multi-selection (default: false)

### `setClearable(bool $clearable = true)`

Allow null value in non-multiple selection (default: false)

### `setDisplayAsList()`

Display as a list (the default value):

* radio if multiple=false
* checkboxes if multiple=true

### `setDisplayAsDropdown()`

Display as a classic dropdown.

### `setMaxSelected(int $maxSelected)`

Set a maximum item selection (multiple only).
Default: unlimited.

### `setMaxSelectedUnlimited()`

Unset a maximum item selection (multiple only).

### `setInline(bool $inline = true)`

Display an inline checklist (if multiple + display=list).

### `setIdAttribute(string $idAttribute)`

Set the id name attribute of options (default: "id").

### `setOptionsLinkedTo(string ...$fieldKeys)`

Thanks to this feature, you can link the dataset (meaning: the `options`) of the select to another field of the form (or even: to some other fields). In this case, the `options` array must be indexed with the value of the linked field.

For instance:

```php
SharpFormSelectField::make(
    'brand',
    [
        'France' => [
            ['id'=>1, 'label'=>'Renault'],
            ['id'=>2, 'label'=>'Peugeot'],
        ], 
        'Germany' => [
            ['id'=>3, 'label'=>'Audi'],
            ['id'=>4, 'label'=>'Mercedes'],
        ]
    ]
)->setOptionsLinkedTo('country')
```

This would work on relation with a `country` form field, which may be valued with "France" or "Germany".

In some cases you may want to depend on more than one field; you must add a nested level in the `options` array:

```php
SharpFormSelectField::make(
    'model',
    [
        'France' => [
            1 => [['id'=>67, 'label'=>'Clio'], ...],
            2 => ...
        ], 
        'Germany' => [
            3 => [['id'=>98, 'label'=>'A4'], ...],
            4 => ...
        ]
    ]
)->setOptionsLinkedTo('country', 'brand')
```

## Formatter

* `toFront`: expects
  * a single id value if multiple=false
  * an array of id values OR an array of models if multiple=true

* `fromFront`: returns
  * a single id value if multiple=false
  * an array of arrays with the "id" key otherwise:

```php
[
    ['id' => 1],
    ['id' => 2]
]
```