List Box (Control)

Use a list box to display a list of items in which the number of items may vary. Items may either be choices, or they may identify objects by their names.

Display the items in a list box in an order that is meaningful to a user, such as alphabetic order, numeric order, chronological order, or some other order. For example, display modem baud rates in numeric order.

When the cursor is on a list item that labels a viewable object, make presenting that object the default action.

Design list boxes with either a single, browse, multiple, or extended selection model.

Provide first-letter cursor navigation in a list box.

In a scrollable list box, do not allow the cursor to wrap.

Display the active cursor as an element cursor on the appropriate list item.

When the user presses ↑ or ↓, navigate to the previous and next items in the list box, respectively.

If a list box can be scrolled horizontally, make it a tab group.

If a list box can be scrolled horizontally, then when focus is in the list box, allow ← and → to scroll left and right by one character width, and Ctrl ← and Ctrl → to scroll left and right by a larger amount.

Design a list box to be a tab group.

Provide the list box with an area for presenting a list of labels as items.

Provide vertical scroll bars when some of the list items are not visible in the list box.

Arrange the list items vertically.

Use different cursor visuals when the list box is in add mode from the one used in normal mode.

Design a list box to be large enough to display a minimum of six list items at a time to provide context to the user.

Make list boxes at least wide enough to display list items of average width.

When a user increases the size of the window in which the list box is displayed, increase the size of the list box so that more items can be seen.

When a user decreases the size of the window in which the list box is displayed, decrease the size of the list box so that fewer items can be seen, unless reducing the size of the list box will prevent the list box from displaying two list items.

Provide horizontal scroll bars when items are wider than the list box.

In normal mode, use a solid box around the item as the cursor visual.

In add mode, use a dashed box around the item as the cursor visual.

If a window can be decreased in size so much that two items in the list cannot be seen, consider allowing the window to be scrolled or using a drop-down list box instead of a list box.