Dropdown Component

Function: a!dropdownField()

Displays a list of choices for the user to select one item and saves a value based on the selected choice.

If the user may select none, one, or many of the choices, use either the checkbox component or a multiple dropdown component.

If there aren't many choices and users would benefit from easily seeing them all at once, consider using radio buttons.

Parameters

Name Keyword Types Description

Label

label

Text

Text to display as the field label.

Label Position

labelPosition

Text

Determines where the label appears. Valid values:

  • "ABOVE" (default) Displays the label above the component.
  • "ADJACENT" Displays the label to the left of the component.
  • "JUSTIFIED" Aligns the label alongside the component starting at the edge of the page.
  • "COLLAPSED" Hides the label. The label will still be read by screen readers; see accessibility considerations for more information.

Instructions

instructions

Text

Supplemental text about this field.

Required

required

Boolean

Determines if a value is required to submit the form. Default: false.

Disabled

disabled

Boolean

Determines if the field should display as potentially editable but grayed out. Default: false.

Choice Labels

choiceLabels

List of Text String

Array of options for the user to select.

Choice Values

choiceValues

List of Variant

Array of values associated with the available choices.

Placeholder

placeholder

Text

Text to display when nothing is selected and the value is null.

Selected Value

value

Any Type

Value of the choice to display as selected.

Validations

validations

List of Text String

Validation errors to display below the field when the value is not null.

Save Selection To

saveInto

List of Save

One or more variables that are updated with the choice value when the user changes the selection. Use a!save() to save a modified or alternative value to a variable.

Validation Group

validationGroup

Text

When present, this field is only validated when a button in the same validation group is pressed. See this recipe for more information about how to use validation groups.

Required Message

requiredMessage

Text

Custom message to display when the field's value is required and not provided.

Help Tooltip

helpTooltip

Text

Displays a help icon with the specified text as a tooltip. The tooltip displays a maximum of 500 characters. The help icon does not show when the label position is "COLLAPSED".

Accessibility Text

accessibilityText

Text

Additional text to be announced by screen readers. Used only for accessibility; produces no visible change.

Visibility

showWhen

Boolean

Determines whether the component is displayed on the interface. When set to false, the component is hidden and is not evaluated. Default: true.

Search Display

searchDisplay

Text

Determines when a search box displays above the options. Valid values: "AUTO" (default), "ON", "OFF". When set to "AUTO", the search box displays if there are more than 11 options.

Notes

  • To allow users on web to clear the selected value, text must be specified for the placeholder parameter. Users can always clear the value on the Appian for Mobile application.
  • Options display in the same order as defined in the Choice Labels parameter. The Choice Labels parameter cannot be null.
  • Passing a null value to the dropdown's Selected Value parameter causes the placeholder text to appear selected. The Placeholder and Selected Value parameter cannot both be null.
  • The Choice Labels list and Choice Values list must be the same length.
  • Choice Values cannot contain nulls or duplicate values.
  • If you are trying to decide whether to use a dropdown with search or a picker component, keep in mind that the dropdown search runs client-side and the performance cost of loading options happens on initial load whereas the picker search runs server-side and the performance cost of loading options happens while the user is searching. For small sets of options, we recommend using the dropdown component.

Examples

Copy and paste an example into the INTERFACE DEFINITION in EXPRESSION MODE to see it displayed.

Dropdown with the First Choice Selected by Default and Search on Auto

Since the searchDisplay parameter is set to AUTO and the number of choiceValues is less than 12, no search box will be displayed.

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=a!localVariables(
  local!language: "en_US",
  a!dropdownField(
    label: "Language",
    instructions: "In which language are you most proficient?",
    choiceLabels: {
      "English",
      "Spanish",
      "French",
      "German"
    },
    choiceValues: {
      "en_US",
      "es_ES",
      "fr_FR",
      "de_DE"
    },
    value: local!language,
    saveInto: local!language,
    placeholder: "Select a language",
    searchDisplay: "AUTO"
  )
)

Displays the following:

Since the searchDisplay parameter is set to AUTO and the number of choiceValues is more than 11, a search box will be displayed.

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=a!localVariables(
  local!language: "en_US",
  a!dropdownField(
    label: "Language",
    instructions: "In which language are you most proficient?",
    choiceLabels: {
      "English (US)",
      "Arabic",
      "Chinese (Simplified)",
      "Chinese (Traditional)",
      "Spanish",
      "French",
      "German",
      "Japanese",
      "Korean",
      "Polish",
      "Portuguese",
      "Russian"
    },
    choiceValues: {
      "en_US",
      "ar",
      "zh_CN",
      "zh_HK",
      "es_ES",
      "fr_FR",
      "de_DE",
      "ja",
      "ko",
      "pl",
      "pt",
      "ru"
    },
    value: local!language,
    saveInto: local!language,
    placeholder: "Select a language",
    searchDisplay: "AUTO"
  )
)

Displays the following:

Dropdown with No Choice Selected by Default and Search On

Since the searchDisplay parameter is set to ON, even though the number of choiceValues is less than 12, a search box will be displayed.

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=a!localVariables(
  local!language: null,
  a!dropdownField(
    label: "Language",
    instructions: "In which language are you most proficient?",
    choiceLabels: {
      "English",
      "Spanish",
      "French",
      "German"
    },
    choiceValues: {
      "en_US",
      "es_ES",
      "fr_FR",
      "de_DE"
    },
    value: local!language,
    saveInto: local!language,
    placeholder: "Select a language",
    searchDisplay: "ON"
  )
)

Displays the following:

The following patterns include usage of the Dropdown Component.

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