Accessibility in Blazor MultiSelect Dropdown Component
21 Jan 20223 minutes to read
The MultiSelect component has been designed, keeping in mind the WAI-ARIA specifications, and applies the WAI-ARIA roles, states, and properties along with keyboard support. This component is characterized by complete keyboard interaction support and ARIA accessibility support that makes it easy for people who use assistive technologies (AT) or those who completely rely on keyboard navigation.
ARIA attributes
The MultiSelect component uses the Listbox role, and each list item has an option role. The following
ARIA attributes denotes the MultiSelect state:
| Properties | Functionalities |
|---|---|
| aria-haspopup | Indicates whether the MultiSelect input element has a popup list or not. |
| aria-expanded | Indicates whether the popup list has expanded or not. |
| aria-selected | Indicates the selected option. |
| aria-readonly | Indicates the readonly state of the MultiSelect element. |
| aria-disabled | Indicates whether the MultiSelect component is in disabled state or not. |
| aria-activedescendent | This attribute holds the ID of the active list item to focus its descendant child element. |
| aria-owns | This attribute contains the ID of the popup list to indicate popup as a child element. |
Keyboard interaction
You can use the following key shortcuts to access the MultiSelect without interruptions:
| Keyboard shortcuts | Actions |
|---|---|
| Arrow Down | Sets focus at the first item in the MultiSelect when no item is selected. Otherwise, moves focus next to the currently selected item. |
| Arrow Up | Moves focus previous to the currently selected one. |
| Page Down | Scrolls down to the next page and set focus to the first item when popup list opens. |
| Page Up | Scrolls up to the previous page and set focus to the first item when popup list opens. |
| Enter | Selects the focused item, and when it is in an close state the popup list opens. |
| Tab | Focuses on the next TabIndex element on the page when the popup is closed. Otherwise, closes the popup list and remains the focus of the component. |
| Shift + tab | Focuses on the previous TabIndex element on the page when the popup is closed. Otherwise, closes the popup list and remains the focus of the component. |
| Alt + Down | Opens the popup list. |
| Alt + Up | Closes the popup list. |
| Esc(Escape) | Closes the popup list when it is in an open state and the currently selected item remains the same. |
| Home | Sets focus to the first item. |
| End | Sets focus to the last item. |