List box format - %n.mls[options]
This format supplies a simple list-box facility. The corresponding arguments are
an array of CHARACTER strings, an INTEGER argument giving the size of the array
and an INTEGER argument that both sets the initial selection and returns the
i=winio@('Select a Greek letter: %7.3ls',greek,4L,k)
The characters "7.3" before "ls" specify the width of the list box (as the
number of characters) and the depth of the list box (as the number of lines).
Pre-setting k to 1 would cause "alpha" to be already highlighted when
the window is displayed. If the user selects "beta", then k set to 2. If k
were pre-set to zero, none of the items would be initially selected. If the
user were to exit without making a selection, k would keep its pre-set
The grave accent (`) may be used with %ls to produce a drop-down combo box
rather than a list box (for an editable combo box see %el - Editable Combo Box
). The caret (^) character is used in association with a call-back function.
This function will be called whenever an item is selected.
(See also the LISTBOX_ITEM_SELECTED parameter in
For a list box (i.e. when a grave accent modifier is not used), the option
hscrollbar provides a horizontal scroll bar whilst the option multicolumn
provides a multiple column display. For example:
Combining hscrollbar with multicolumn gives a horizontal scroll bar that selects
one column at a time.