The ComboBox control has been designed, keeping in mind the WAI-ARIA specifications, and applies
the WAI-ARIA roles, states, and properties along with keyboard support. This control 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.
The ComboBox control uses the combobox role, and each list item has an option role. The following
ARIA attributes denote the ComboBox state.
| Properties | Functionalities |
|---|---|
| aria-haspopup | Indicates whether the ComboBox 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 ComboBox element. |
| aria-disabled | Indicates whether the ComboBox control is in a 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. |
| aria-autocomplete | This attribute contains the ‘both’ to a list of options shows and the currently selected suggestion also shows inline. |
You can use the following key shortcuts to access the ComboBox without interruptions.
| Keyboard shortcuts | Actions |
|---|---|
| Arrow Down | Selects the first item in the ComboBox when no item selected. Otherwise, selects the item next to the currently selected item. |
| Arrow Up | Selects the item previous to the currently selected one. |
| Page Down | Scrolls down to the next page and selects the first item when popup list opens. |
| Page Up | Scrolls up to the previous page and selects the first item when popup list opens. |
| Enter | Selects the focused item and popup list closes when it is in open state. |
| 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 control. |
| 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 control. |
| Alt + Down | Open the popup list |
| Alt + Up | Close 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 | Cursor moves to before of first character in input |
| End | Cursor moves to next of last character in input |
In the following sample, focus the ComboBox control using alt+t keys.
@Html.EJS().ComboBox("games").Placeholder("Select a game").PopupHeight("200px").DataSource((IEnumerable<object>)ViewBag.data).Render()
<script>
document.onkeyup = function (e) {
if (e.altKey && e.keyCode === 84 /* t */) {
var dropObj = document.getElementById("games"); //to get dropdown list object
dropObj.ej2_instances[0].focusIn(); // call the focusIn method to focus the element.
}
};
</script>using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;
namespace WebApplication1.Controllers
{
public class ComboBoxController : Controller
{
public ActionResult accessibility()
{
ViewBag.data = new string[] { "Badminton", "Basketball", "Cricket", "Football", "Golf", "Gymnastics", "Hockey", "Tennis" };
return View();
}
}
}