Forms

Form Behavior is a controller modifier used for easily adding form functionality to a back-end page. The behavior provides three pages called Create, Update and Preview. The Preview page is a read-only version of the Update page. When you use the form behavior you don't need to define the create, update and preview actions in the controller - the behavior does it for you. However you should provide the corresponding view files.

Form behavior depends on form field definitions and a model class. In order to use the form behavior you should add it to the $implement property of the controller class. Also, the $formConfig class property should be defined and its value should refer to the YAML file used for configuring the behavior options.

namespace Acme\Blog\Controllers;

class Categories extends \Backend\Classes\Controller
{
    public $implement = [
        \Backend\Behaviors\FormController::class
    ];

    public $formConfig = 'config_form.yaml';
}

Note: Very often the form and list behavior are used together in a same controller.

# Configuring the Form Behavior

The configuration file referred in the $formConfig property is defined in YAML format. The file should be placed into the controller's views directory. Below is an example of a typical form behavior configuration file.

# ===================================
#  Form Behavior Config
# ===================================

name: Blog Category
form: $/acme/blog/models/post/fields.yaml
modelClass: Acme\Blog\Post

create:
    title: New Blog Post

update:
    title: Edit Blog Post

preview:
    title: View Blog Post

The following fields are required in the form configuration file.

The configuration options listed below are optional. Define them if you want the form behavior to support the Create, Update or Preview pages.

# Create Page

To support the Create page add the following configuration to the YAML file.

create:
    title: New Blog Post
    redirect: acme/blog/posts/update/:id
    redirectClose: acme/blog/posts

The following configuration options are supported for the Create page.

# Update Page

To support the Update page add the following configuration to the YAML file.

update:
    title: Edit Blog Post
    redirect: acme/blog/posts

The following configuration options are supported for the Update page.

# Preview Page

To support the Preview page add the following configuration to the YAML file:

preview:
    title: View Blog Post

The following configuration options are supported for the Preview page.

# Custom Messages

Specify the customMessages option to override the default messages used by the Form Controller. The values can be plain text or can refer to a localization string.

customMessages:
    notFound: Did not find the thing
    flashCreate: New thing created
    flashUpdate: Updated that thing
    flashDelete: Thing is gone

You may also modify messages in the context of the form being displayed. The following will override the notFound message for the update context only.

update:
    customMessages:
        notFound: Nothing found when updating

The following messages are available to override as custom messages.

# Defining Form Fields

Form fields are defined with the YAML file. The form fields configuration is used by the form behavior for creating the form controls and binding them to the model fields. The file is placed to a subdirectory of the models directory of a plugin. The subdirectory name matches the model class name written in lowercase. The file name doesn't matter, but fields.yaml and form_fields.yaml are common names. Example form fields file location:

├── plugins
|   └── acme
|       └── blog
|           └── models
|               ├── post            <== Config Directory
|               |   └── fields.yaml <== Config File
|               └── Post.php        <== Model Class

Fields can be placed in three areas, the outside area, primary tabs or secondary tabs. The next example shows the typical contents of a form fields definition file.

# ===================================
#  Form Field Definitions
# ===================================

fields:
    blog_title:
        label: Blog Title
        description: The title for this blog

    published_at:
        label: Published date
        description: When this blog post was published
        type: datepicker

    # [...]

tabs:
    fields:
        # [...]

secondaryTabs:
    fields:
        # [...]

# Field Options

For each field you can specify these options (where applicable):

# Nested Field Selection

Fields from related models can be rendered with the Relation Widget or the Relation Manager. However, if the relationship type is singular, or a jsonable array, you may use a nested field type using the relation[field] definition.

avatar[name]:
    label: Avatar
    comment: will be saved in the Avatar table

The above example would fetch and save the value in PHP equivalent of $record->avatar->name or $record->avatar['name'] respectively.

# Tab Options

For each tab definition, namely tabs and secondaryTabs, you can specify these options:

tabs:
    stretch: true
    defaultTab: User
    cssClass: text-blue
    lazy:
        - Groups
    paneCssClass:
        1: first-tab
        2: second-tab
    icons:
        User: icon-user
        Groups: icon-group

    fields:
        username:
            type: text
            label: Username
            tab: User

        groups:
            type: relation
            label: Groups
            tab: Groups

# Available Field Types

There are various native field types that can be used for the type setting. For basic UI elements, take a look at the available UI elements. For more advanced form fields, a form widget can be used instead.

# Text

text - renders a single line text box. This is the default type used if none is specified.

blog_title:
    label: Blog Title
    type: text

# Number

number - renders a single line text box that takes numbers only.

your_age:
    label: Your Age
    type: number
    step: 1  # defaults to 'any'
    min: 1   # defaults to not present
    max: 100 # defaults to not present

If you would like to validate this field server-side on save to ensure that it is numeric, please use the $rules property on your model, like so:

/**
 * @var array Validation rules
 */
public $rules = [
    'your_age' => 'numeric',
];

For more information on model validation, please visit the documentation page (opens new window).

# Password

password - renders a single line password field.

user_password:
    label: Password
    type: password

# Email

email - renders a single line text box with the type of email, triggering an email-specialised keyboard in mobile browsers.

user_email:
    label: Email Address
    type: email

If you would like to validate this field on save to ensure that it is a properly-formatted email address, please use the $rules property on your model, like so:

/**
 * @var array Validation rules
 */
public $rules = [
    'user_email' => 'email',
];

For more information on model validation, please visit the documentation page (opens new window).

# Textarea

textarea - renders a multiline text box. A size can also be specified with possible values: tiny, small, large, huge, giant.

blog_contents:
    label: Contents
    type: textarea
    size: large

# Dropdown

dropdown - renders a dropdown with specified options. There are a number of ways to provide the dropdown options, most of them involve specify the options value.

Option values only, where the values and labels are the same.

status_type:
    label: Blog Post Status
    type: dropdown
    default: published
    options:
        draft
        published
        archived

Options with key-value pair, where the value and label are independently specified.

status_type:
    label: Blog Post Status
    type: dropdown
    default: published
    options:
        draft: Draft
        published: Published
        archived: Archived

The next approaches involve using the model class in your plugin or application codebase. If the options value is omitted, the framework expects a method with the name get*FieldName*Options to be defined in the model.

Using the example below, the model class is expected to have the getStatusTypeOptions method. The first argument of this method is the current value of this field and the second is the current data object for the entire form. This method should return an array of options in the format key => label.

status_type:
    label: Blog Post Status
    type: dropdown

This is an example of the model class method that supplies the dropdown options. Notice that the method name matches the column name in TitleCase format.

public function getStatusTypeOptions($value, $formData)
{
    return ['all' => 'All', ...];
}

You may also define a catch-all method that works as a fallback in cases where the dedicated method name is not defined, which will be used for all dropdown field types for the model.

The first argument of this method is the field name, the second is the current value of the field, and the third is the current data object for the entire form. It should return an array of options in the format key => label.

public function getDropdownOptions($fieldName, $value, $formData)
{
    if ($fieldName == 'status') {
        return ['all' => 'All', ...];
    }
    else {
        return ['' => '-- none --'];
    }
}

To use a custom method name, specify it explicitly in the options parameter and this will match exactly to the method name defined in the model.

In the next example the listStatuses method should be defined in the model class. This method receives all the same arguments as the getDropdownOptions method, and should return an array of options in the format key => label.

status:
    label: Blog Post Status
    type: dropdown
    options: listStatuses

This is an example of the model class custom method that supplies the dropdown options.

public function listStatuses($fieldName, $value, $formData)
{
    return ['published' => 'Published', ...];
}

To add a custom icon for every option rendered in the dropdown field, you may specify the options as a multidimensional array with the following format key => [label-text, label-icon].

public function listStatuses($fieldName, $value, $formData)
{
    return [
        'published' => ['Published', 'icon-check-circle'],
        'unpublished' => ['Unpublished', 'icon-minus-circle'],
        'draft' => ['Draft', 'icon-clock-o']
    ];
}

Displaying a custom color is also supported by specifying the options as an array with the format key => [label-text, label-color] where the color is a hex value beginning with a hash (#).

public function listStatuses($fieldName, $value, $formData)
{
    return [
        'published' => ['Published', '#666666'],
        'unpublished' => ['Unpublished', '#ff9999'],
        'draft' => ['Draft', '#ff0000']
    ];
}

If you want to call a method on an external class, you may do it by calling a static method on any fully qualified object. Simply specify the ClassName::method syntax as a string in the options parameter.

status:
    label: Blog Post Status
    type: dropdown
    options: \MyAuthor\MyPlugin\Helpers\FormHelper::staticMethodOptions

This examples shows the static method defined on any helper class. The first argument is the Model object and the second argument is the form field definition.

public static function staticMethodOptions($model, $formField)
{
    return ['published' => 'Published', ...];
}

To handle cases when there is no value set on the model, you may specify an emptyOption value to include an empty option that can be reselected.

status:
    label: Blog Post Status
    type: dropdown
    emptyOption: -- no status --

Alternatively you may use the placeholder option to use a "one-way" empty option that cannot be reselected.

status:
    label: Blog Post Status
    type: dropdown
    placeholder: -- select a status --

By default the dropdown has a searching feature, allowing quick selection of a value. This can be disabled by setting the showSearch option to false.

status:
    label: Blog Post Status
    type: dropdown
    showSearch: false

# Radio List

radio - renders a list of radio options, where only one item can be selected at a time.

security_level:
    label: Access Level
    type: radio
    default: guests
    options:
        all: All
        registered: Registered only
        guests: Guests only

Radio lists can also support a secondary description.

security_level:
    label: Access Level
    type: radio
    options:
        all: [All, Guests and customers will be able to access this page.]
        registered: [Registered only, Only logged in member will be able to access this page.]
        guests: [Guests only, Only guest users will be able to access this page.]

Radio lists support the same methods for defining the options as the dropdown field type. For radio lists the method could return either the simple array: key => value or an array of arrays for providing the descriptions: key => [label, description]. Options can be displayed inline with each other instead of in separate rows by specifying cssClass: 'inline-options' on the radio field config.

# Balloon Selector

balloon-selector - renders a list, where only one item can be selected at a time.

gender:
    label: Gender
    type: balloon-selector
    default: female
    options:
        female: Female
        male: Male

Balloon selectors support the same methods for defining the options as the dropdown field type.

# Checkbox

checkbox - renders a single checkbox.

show_content:
    label: Display content
    type: checkbox
    default: true

# Checkbox List

checkboxlist - renders a list of checkboxes.

permissions:
    label: Permissions
    type: checkboxlist
    options:
        open_account: Open account
        close_account: Close account
        modify_account: Modify account

Checkbox lists support the same methods for defining the options as the dropdown field type and also support secondary descriptions, found in the radio field type.

permissions:
    type: checkboxlist
    options: listPermissions

Options can be displayed inline with each other instead of in separate rows by specifying inline-options as the cssClass on the field config.

permissions:
    type: checkboxlist
    cssClass: inline-options

A quick select menu with "Select All" and "Select None" buttons will become visible when the list has greater than 10 items. To explicitly enable these buttons, use the quickselect option.

permissions:
    type: checkboxlist
    quickselect: true

# Switch

switch - renders a switchbox.

show_content:
    label: Display content
    type: switch
    comment: Flick this switch to display content

You may customize the switch text by passing an array to the options value with false and true labels.

show_content:
    label: Display content
    type: switch
    options:
        - Nope
        - Yeah

# Widget

widget - renders a custom form widget, the type field can refer directly to the class name of the widget or the registered alias name.

blog_content:
    type: Backend\FormWidgets\RichEditor
    size: huge

# Available UI Elements

There are non function UI elements that can be included in forms to help with the layout design.

# Section

section - renders a section heading and subheading. The label and comment values are optional and contain the content for the heading and subheading.

_section1:
    label: User details
    type: section
    comment: This section contains details about the user.

# Hint

hint - identical to a partial field but renders inside a hint container that can be hidden by the user.

_hint1:
    type: hint
    path: content_field

A hint supports content inline to the field. The label and comment values are optional and contain the content for the heading and subheading. You may also use Markdown syntax for the values.

_tip1:
    type: hint
    mode: tip
    label: Pro Tip
    comment: Always check to make sure this field is populated.

The mode option supports the values: tip, info, warning, danger, success

_warning1:
    type: hint
    mode: warning
    label: Always wash your hands
    comment: This is good for stopping the spread of germs.

# Horizontal Rule

ruler - renders a horizontal rule to break up the form contents

_ruler1:
    type: ruler

# Partial

partial - renders a partial, the path value can refer to a partial view file otherwise the field name is used as the partial name. Inside the partial these variables are available: $value is the default field value, $model is the model used for the field and $field is the configured class object Backend\Classes\FormField.

content:
    type: partial
    path: $/acme/blog/models/comments/_content_field.htm

# Form Widgets

There are various form widgets included as standard, although it is common for plugins to provide their own custom form widgets. You can read more on the Form Widgets article.

# Code Editor

codeeditor - renders a plaintext editor for formatted code or markup. Note the options may be inherited by the code editor preferences defined for the Administrator in the back-end.

css_content:
    type: codeeditor
    size: huge
    language: html

# Color Picker

colorpicker - renders controls to select a hexadecimal color value.

color:
    label: Background
    type: colorpicker

There are two ways to provide the available colors for the colorpicker. The first method defines the availableColors directly as a list of hex color codes in the YAML file:

color:
    label: Background
    type: colorpicker
    availableColors: ['#000000', '#111111', '#222222']

The second method uses a specific method declared in the model class. This method should return an array of hex colors in the same format as in the example above. The first argument of this method is the field name, the second is the currect value of the field, and the third is the current data object for the entire form.

color:
    label: Background
    type: colorpicker
    availableColors: myColorList

Supplying the available colors in the model class:

public function myColorList($fieldName, $value, $formData)
{
    return ['#000000', '#111111', '#222222']
}

If the availableColors field in not defined in the YAML file, the colorpicker uses a set of 20 default colors.

# Data Table

datatable - renders an editable table of records, formatted as a grid. Cell content can be editable directly in the grid, allowing for the management of several rows and columns of information.

data:
    type: datatable
    adding: true
    deleting: true
    columns: []
    recordsPerPage: false
    searching: false

Note: In order to use this with a model, the field should be defined in the jsonable property or anything that can handle storing as an array.

# Table configuration

The following lists the configuration values of the data table widget itself.

# Column configuration

The data table widget allows for the specification of columns as an array via the columns configuration variable. Each column should use the field name as a key, and the following configuration variables to set up the field.

Example:

columns:
    id:
        type: string
        title: ID
        validation:
            integer:
                message: Please enter a number
    name:
        type: string
        title: Name

# Column validation

Column cells can be validated against the below types of validation. Validation should be specified as an array, with the type of validation used as a key, and an optional message specified as the message attrbute for that validation.

# Date Picker

datepicker - renders a text field used for selecting date and times.

published_at:
    label: Published
    type: datepicker
    mode: date

# File Upload

fileupload - renders a file uploader for images or regular files.

avatar:
    label: Avatar
    type: fileupload
    mode: image
    imageHeight: 260
    imageWidth: 260

Note: Unlike the Media Finder form widget, the File Upload form widget uses database file attachments so the field name be that of an attachOne or attachMany relationship attribute on your associated model.

# Markdown Editor

markdown - renders a basic editor for markdown formatted text.

md_content:
    type: markdown
    size: huge
    mode: split

# Media Finder

mediafinder - renders a field for selecting an item from the media manager library. Expanding the field displays the media manager to locate a file. The resulting selection is a string as the relative path to the file.

whitepaper_file:
    label: Whitepaper PDF
    type: mediafinder

Set the mode to image to display a preview of the selected image.

background_image:
    label: Background Image
    type: mediafinder
    mode: image

Note: Unlike the File Upload form widget, the Media Finder form widget stores its data as a string representing the path to the media files selected within the Media Library. It should associate to a normal attribute on your model.

# Nested Form

nestedform - renders a nested form using a related record or jsonable attribute. Fields can be defined inline or using an external yaml file.

content:
    type: nestedform
    showPanel: false
    form:
        fields:
            added_at:
                label: Date added
                type: datepicker
            details:
                label: Details
                type: textarea
            title:
                label: This the title
                type: text

Pass a string to the form option to reference an external yaml file.

profile:
    label: Profile
    type: nestedform
    form: $/october/demo/models/profile/fields.yaml

# Record Finder

recordfinder - renders a field with details of a related record. Expanding the field displays a popup list to search large amounts of records. Supported by singular relationships only.

user:
    label: User
    type: recordfinder
    list: ~/plugins/rainlab/user/models/user/columns.yaml
    recordsPerPage: 10
    title: Find Record
    prompt: Click the Find button to find a user
    nameFrom: name
    descriptionFrom: email

# Relation

relation - renders either a dropdown or checkbox list according to the field relation type. Singular relationships display a dropdown, multiple relationships display a checkbox list. The label used for displaying each relation is sourced by the nameFrom or select definition.

categories:
    label: Categories
    type: relation
    nameFrom: title

Alternatively, you may populate the label using a custom select statement. Any valid SQL statement works here.

user:
    label: User
    type: relation
    select: concat(first_name, ' ', last_name)

You can also provide a model scope to use to filter the results with the scope property.

user:
    label: User
    type: relation
    scope: withTrashed

If the controller implements the Relation Controller behavior and the field is defined there, then it will be displayed using this definition. Set the useController property to false to disable this functionality.

countries:
    label: Categories
    type: relation
    useController: false

# Repeater

repeater - renders a repeating set of form fields using a related record or jsonable attribute.

extra_information:
    type: repeater
    titleFrom: title_when_collapsed
    form:
        fields:
            added_at:
                label: Date added
                type: datepicker
            details:
                label: Details
                type: textarea
            title_when_collapsed:
                label: This field is the title when collapsed
                type: text

The repeater field supports a group mode which allows a custom set of fields to be chosen for each iteration.

content:
    type: repeater
    prompt: Add content block
    groups: $/acme/blog/config/repeater_fields.yaml

This is an example of a group configuration file, which would be located in /plugins/acme/blog/config/repeater_fields.yaml. Alternatively these definitions could be specified inline with the repeater.

textarea:
    name: Textarea
    description: Basic text field
    icon: icon-file-text-o
    fields:
        text_area:
            label: Text Content
            type: textarea
            size: large

quote:
    name: Quote
    description: Quote item
    icon: icon-quote-right
    fields:
        quote_position:
            span: auto
            label: Quote Position
            type: radio
            options:
                left: Left
                center: Center
                right: Right
        quote_content:
            span: auto
            label: Details
            type: textarea

Each group must specify a unique key and the definition supports the following options.

Note: The group key is stored along with the saved data as the _group attribute. This can be customized with the groupKeyFrom option.

# Rich editor / WYSIWYG

richeditor - renders a visual editor for rich formatted text, also known as a WYSIWYG editor.

html_content:
    type: richeditor
    toolbarButtons: bold|italic
    size: huge

The available toolbar buttons are:

fullscreen, bold, italic, underline, strikeThrough, subscript, superscript, fontFamily, fontSize, |, color, emoticons, inlineStyle, paragraphStyle, |, paragraphFormat, align, formatOL, formatUL, outdent, indent, quote, insertHR, -, insertLink, insertImage, insertVideo, insertAudio, insertFile, insertTable, undo, redo, clearFormatting, selectAll, html

Note: | will insert a vertical separator line in the toolbar and - a horizontal one.

# Sensitive

sensitive - renders a revealable password field that can be used for sensitive information such as API keys or secrets, configuration values, etc. A sensitive field can be toggled visible and hidden at the user's request.

A sensitive field that contains a previously entered value will have the value replaced with a placeholder value on load, preventing the value from being guessed by length or copied. Upon revealing the value, the original value is retrieved by AJAX and populated into the field.

api_secret:
    type: sensitive
    allowCopy: false
    hideOnTabChange: true

# Tag list

taglist - renders a field for inputting a list of tags.

tags:
    type: taglist
    separator: space

A tag list support the same methods for defining the options as the dropdown field type.

tags:
    type: taglist
    options:
        - Red
        - Blue
        - Orange

You may use the mode called relation where the field name is a many-to-many relationship. This will automatically source and assign tags via the relationship. If custom tags are supported, they will be created before assignment.

tags:
    type: taglist
    mode: relation

# Form Views

For each page your form supports Create, Update and Preview you should provide a view file with the corresponding name - create.htm, update.htm and preview.htm.

The form behavior adds two methods to the controller class: formRender and formRenderPreview. These methods render the form controls configured with the YAML file described above.

# Create View

The create.htm view represents the Create page that allows users to create new records. A typical Create page contains breadcrumbs, the form itself, and the form buttons. The data-request attribute should refer to the onSave AJAX handler provided by the form behavior. Below is a contents of the typical create.htm form.

<?= Form::open(['class'=>'layout']) ?>

    <div class="layout-row">
        <?= $this->formRender() ?>
    </div>

    <div class="form-buttons">
        <div class="loading-indicator-container">
            <button
                type="button"
                data-request="onSave"
                data-request-data="close:true"
                data-hotkey="ctrl+enter, cmd+enter"
                data-load-indicator="Creating Category..."
                class="btn btn-default">
                Create and Close
            </button>
            <span class="btn-text">
                or <a href="<?= Backend::url('acme/blog/categories') ?>">Cancel</a>
            </span>
        </div>
    </div>

<?= Form::close() ?>

# Update View

The update.htm view represents the Update page that allows users to update or delete existing records. A typical Update page contains breadcrumbs, the form itself, and the form buttons. The Update page is very similar to the Create page, but usually has the Delete button. The data-request attribute should refer to the onSave AJAX handler provided by the form behavior. Below is a contents of the typical update.htm form.

<?= Form::open(['class'=>'layout']) ?>

    <div class="layout-row">
        <?= $this->formRender() ?>
    </div>

    <div class="form-buttons">
        <div class="loading-indicator-container">
            <button
                type="button"
                data-request="onSave"
                data-request-data="close:true"
                data-hotkey="ctrl+enter, cmd+enter"
                data-load-indicator="Saving Category..."
                class="btn btn-default">
                Save and Close
            </button>
            <button
                type="button"
                class="oc-icon-trash-o btn-icon danger pull-right"
                data-request="onDelete"
                data-load-indicator="Deleting Category..."
                data-request-confirm="Do you really want to delete this category?">
            </button>
            <span class="btn-text">
                or <a href="<?= Backend::url('acme/blog/categories') ?>">Cancel</a>
            </span>
        </div>
    </div>

<?= Form::close() ?>

# Preview View

The preview.htm view represents the Preview page that allows users to preview existing records in the read-only mode. A typical Preview page contains breadcrumbs and the form itself. Below is a contents of the typical preview.htm form.

<div class="form-preview">
    <?= $this->formRenderPreview() ?>
</div>

# Applying Conditions to Fields

Sometimes you may want to manipulate the value or appearance of a form field under certain conditions, for example, you may want to hide an input if a checkbox is ticked. There are a few ways you can do this, either by using the trigger API or field dependencies. The input preset converter is primarily used to converting field values. These options are described in more detail below.

# Input Preset Converter

The input preset converter is defined with the preset form field option and allows you to convert text entered into an element to a URL, slug or file name value in another input element.

In this example we will automatically fill out the url field value when a user enters text in the title field. If the text Hello world is typed in for the Title, the URL will follow suit with the converted value of /hello-world. This behavior will only occur when the destination field (url) is empty and untouched.

title:
    label: Title

url:
    label: URL
    preset:
        field: title
        type: url

Alternatively, the preset value can also be a string that refers to the field only, the type option will then default to slug.

slug:
    label: Slug
    preset: title

The following options are available for the preset option:

Following are the supported types:

# Trigger Events

Trigger Events are defined with the trigger form field option and is a simple browser based solution that uses JavaScript. It allows you to change elements attributes such as visibility or value, based on another elements' state. Here is a sample definition:

is_delayed:
    label: Send later
    comment: Place a tick in this box if you want to send this message at a later time.
    type: checkbox

send_at:
    label: Send date
    type: datepicker
    cssClass: field-indent
    trigger:
        action: show
        field: is_delayed
        condition: checked

In the above example the send_at form field will only be shown if the is_delayed field is checked. In other words, the field will show (action) if the other form input (field) is checked (condition). The trigger definition specifies these options:

# Field Dependencies

Form fields can declare dependencies on other fields by defining the dependsOn form field option which provides a more robust server side solution for updating fields when their dependencies are modified. When the fields that are declared as dependencies change, the defining field will update using the AJAX framework. This provides an opportunity to interact with the field's properties using the filterFields methods or changing available options to be provided to the field.

country:
    label: Country
    type: dropdown

state:
    label: State
    type: dropdown
    dependsOn: country

In the above example the state form field will refresh when the country field has a changed value. When this occurs, the current form data will be filled in the model so the dropdown options can use it.

public function getCountryOptions()
{
    return ['au' => 'Australia', 'ca' => 'Canada'];
}

public function getStateOptions()
{
    if ($this->country == 'au') {
        return ['act' => 'Capital Territory', 'qld' => 'Queensland', ...];
    }
    elseif ($this->country == 'ca') {
        return ['bc' => 'British Columbia', 'on' => 'Ontario', ...];
    }
}

You can filter the form field definitions by overriding the filterFields method inside the Model used. This allows you to manipulate visibility and other field properties based on the model data. The method takes two arguments $fields will represent an object of the fields already defined by the field configuration and $context represents the active form context.

public function filterFields($fields, $context = null)
{
    if ($this->source_type === 'http') {
        $fields->source_url->hidden = false;
        $fields->git_branch->hidden = true;
    }
    elseif ($this->source_type === 'git') {
        $fields->source_url->hidden = false;
        $fields->git_branch->hidden = false;
    }
    else {
        $fields->source_url->hidden = true;
        $fields->git_branch->hidden = true;
    }
}

The above logic will set the hidden flag on certain fields by checking the value of the Model attribute source_type. This logic will be applied when the form first loads and also when updated by a defined field dependency. For example, here is the associated form field definitions.

source_type:
    label: Source Type
    type: dropdown
    options:
        git: Git
        http: Http
        upload: Upload

source_url:
    label: Source URL
    type: text
    dependsOn: source_type

git_branch:
    label: Git Branch
    type: text
    dependsOn: source_type

You may also extend other models to apply the filterFields logic, see the Filtering Form Fields section for more details.

# Field Facades

Sometimes you may need to display a field while preventing it from being submitted. A field can be defined as a facade by adding an underscore (_) before the name of the field. These fields are purged automatically and no longer saved to the model, such as with the following _map field.

address:
    label: Title
    type: text

_map:
    label: Point your address on the map
    type: mapviewer

# Extending Form Behavior

Sometimes you may wish to modify the default form behavior and there are several ways you can do this.

# Extending the Form Configuration

You may extend the form configuration dynamically using the formGetConfig method.

public function formGetConfig()
{
    $config = $this->asExtension('FormController')->formGetConfig();

    // Set the active tab dynamically
    $config->form['tabs']['activeTab'] = 'Content';

    return $config;
}

# Overriding Controller Action

You can use your own logic for the create, update or preview action method in the controller, then optionally call the Form behavior parent method.

public function update($recordId, $context = null)
{
    //
    // Do any custom code here
    //

    // Call the FormController behavior update() method
    return $this->asExtension('FormController')->update($recordId, $context);
}

# Overriding Controller Redirect

You can specify the URL to redirect to after the model is saved by overriding the formGetRedirectUrl method. This method returns the location to redirect to with relative URLs being treated as backend URLs.

public function formGetRedirectUrl($context = null, $model = null)
{
    return 'https://octobercms.com';
}

# Extending Form Model Query

The lookup query for the form database model can be extended by overriding the formExtendQuery method inside the controller class. This example will ensure that soft deleted records can still be found and updated, by applying the withTrashed scope to the query:

public function formExtendQuery($query)
{
    $query->withTrashed();
}

# Extending Form Fields

You can extend the fields of another controller from outside by calling the extendFormFields static method on the controller class. This method can take three arguments, $form will represent the Form widget object, $model represents the model used by the form and $context is a string containing the form context. Take this controller for example:

class Categories extends \Backend\Classes\Controller
{
    public $implement = [
        \Backend\Behaviors\FormController::class
    ];

    public $formConfig = 'config_form.yaml';
}

Using the extendFormFields method you can add extra fields to any form rendered by this controller. Since this has the potential to affect all forms used by this controller, it is a good idea to check the $model is of the correct type. Here is an example:

Categories::extendFormFields(function($form, $model, $context) {
    if (!$model instanceof MyModel) {
        return;
    }

    $form->addFields([
        'my_field' => [
            'label'   => 'My Field',
            'comment' => 'This is a custom field I have added.',
        ],
    ]);

});

You can also extend the form fields internally by overriding the formExtendFields method inside the controller class. This will only affect the form used by the FormController behavior.

class Categories extends \Backend\Classes\Controller
{
    // ...

    public function formExtendFields($form)
    {
        $form->addFields([...]);
    }
}

The following methods are available on the $form object.

Each method takes an array of fields similar to the form field configuration.

# Filtering Form Fields

As described in the field dependencies section, you may also implement form field filtering by extension by hooking in to the form.filterFields event.

User::extend(function ($model) {
    $model->bindEvent('model.form.filterFields', function ($formWidget, $fields, $context) use ($model) {
        if ($model->source_type === 'http') {
            $fields->source_url->hidden = false;
            $fields->git_branch->hidden = true;
        }
        elseif ($model->source_type === 'git') {
            $fields->source_url->hidden = false;
            $fields->git_branch->hidden = false;
        }
        else {
            $fields->source_url->hidden = true;
            $fields->git_branch->hidden = true;
        }
    });
});

# Validating Form Fields

To validate the fields of your form you can make use of the Validation trait in your model.