LISTBOX(9)LISTBOX(9)NAMElistbox - Create and manipulate listbox widgets
SYNOPSISlistbox pathName ?options?
STANDARD OPTIONS-background-highlightcolor -selectforeground
-borderwidth -highlightthickness -takefocus
-font-relief-width
-foreground-selectbackground -xscrollcommand
-height-selectborderwidth -yscrollcommand
WIDGET-SPECIFIC OPTIONS
-height dist
Specifies the desired height for the window.
-selectmode val
Specifies one of several styles for manipulating the selection.
The value of the option may be arbitrary, but the default bind‐
ings expect it to be either single, browse, multiple, or
extended; the default value is single.
-width dist
Specifies the desired width for the window.
DESCRIPTION
The listbox command creates a new window (given by the pathName argu‐
ment) and makes it into a listbox widget. Additional options,
described above, may be specified on the command line to configure
aspects of the listbox such as its colours, font, text, and relief.
The listbox command returns its pathName argument. At the time this
command is invoked, there must not exist a window named pathName.
A listbox is a widget that displays a list of strings, one per line.
When first created, a new listbox has no elements. Elements may be
added or deleted using widget commands described below. In addition,
one or more elements may be selected as described below.
It is not necessary for all the elements to be displayed in the listbox
window at once; commands described below may be used to change the
view in the window. Listboxes allow scrolling in both directions using
the standard -xscrollcommand and -yscrollcommand options.
INDICES
Many of the widget commands for listboxes take one or more indices as
arguments. An index specifies a particular element of the listbox, in
any of the following ways:
number Specifies the element as a numerical index, where 0 corre‐
sponds to the first element in the listbox.
active Indicates the element that has the location cursor. This
element will be displayed with a highlight rectangle when
the listbox has the keyboard focus, and it is specified
with the activate widget command.
anchor Indicates the anchor point for the selection, which is set
with the selection anchor widget command.
end Indicates the end of the listbox. For some commands this
means just after the last element; for other commands it
means the last element.
@x,y Indicates the element that covers the point in the listbox
window specified by x and y (in pixel coordinates). If no
element covers that point, then the closest element to that
point is used.
In the widget command descriptions below, arguments named index, first,
and last always contain text indices in one of the above forms.
WIDGET COMMAND
The listbox command creates a new Tk command whose name is pathName.
This command may be used to invoke various operations on the widget.
It has the following general form:
pathName option ?arg arg ...?
Option and the args determine the exact behaviour of the command. The
following commands are possible for listbox widgets:
pathName activate index
Sets the active element to the one indicated by index. The
active element is drawn with an underline when the widget has
the input focus, and its index may be retrieved with the index
active.
pathName cget option
Returns the current value of the configuration option given by
option. Option may have any of the values accepted by the list‐
box command.
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no
option is specified, returns a list of all of the available
options for pathName. If one or more option-value pairs are
specified, then the command modifies the given widget option(s)
to have the given value(s); in this case the command returns an
empty string. Option may have any of the values accepted by the
listbox command.
pathName curselection
Returns a list containing the numerical indices of all of the
elements in the listbox that are currently selected. If there
are no elements selected in the listbox then an empty string is
returned.
pathName delete first ?last?
Deletes one or more elements of the listbox. First and last are
indices specifying the first and last elements in the range to
delete. If last isn't specified it defaults to first, i.e. a
single element is deleted.
pathName get first ?last?
If last is omitted, returns the contents of the listbox element
indicated by first. If last is specified, the command returns a
list whose elements are all of the listbox elements between
first and last, inclusive. Both first and last may have any of
the standard forms for indices.
pathName index index
Returns a decimal string giving the integer index value that
corresponds to index.
pathName insert index ?element element ...?
Inserts zero or more new elements in the list just before the
element given by index. If index is specified as end then the
new elements are added to the end of the list. Returns an empty
string.
pathName nearest y
Given a y-coordinate within the listbox window, this command
returns the index of the (visible) listbox element nearest to
that y-coordinate.
pathName see index
Adjust the view in the listbox so that the element given by
index is visible. If the element is already visible then the
command has no effect; if the element is near one edge of the
window then the listbox scrolls to bring the element into view
at the edge; otherwise the listbox scrolls to center the ele‐
ment.
pathName selection option arg
This command is used to adjust the selection within a listbox.
It has several forms, depending on option:
pathName selection anchor index
Sets the selection anchor to the element given by index.
The selection anchor is the end of the selection that is
fixed while dragging out a selection with the mouse. The
index anchor may be used to refer to the anchor element.
pathName selection clear first ?last?
If any of the elements between first and last (inclusive)
are selected, they are deselected. The selection state
is not changed for elements outside this range.
pathName selection includes index
Returns 1 if the element indicated by index is currently
selected, 0 if it isn't.
pathName selection set first ?last?
Selects all of the elements in the range between first
and last, inclusive, without affecting the selection
state of elements outside that range.
pathName size
Returns a decimal string indicating the total number of elements
in the listbox.
pathName xview args
This command is used to query and change the horizontal position
of the information in the widget's window. It can take any of
the following forms:
pathName xview
Returns a list containing two elements. Each element is
a real fraction between 0 and 1; together they describe
the horizontal span that is visible in the window. For
example, if the first element is .2 and the second ele‐
ment is .6, 20% of the listbox's text is off-screen to
the left, the middle 40% is visible in the window, and
40% of the text is off-screen to the right. These are
the same values passed to scrollbars via the -xscrollcom‐
mand option.
pathName xview index
Adjusts the view in the window so that the character
position given by index is displayed at the left edge of
the window. Character positions are defined by the width
of the character 0.
pathName xview moveto fraction
Adjusts the view in the window so that fraction of the
total width of the listbox text is off-screen to the
left. fraction must be a fraction between 0 and 1.
pathName xview scroll number what
This command shifts the view in the window left or right
according to number and what. Number must be an integer.
What must be either units or pages. If what is units,
the view adjusts left or right by number character units
(the width of the 0 character) on the display; if it is
pages then the view adjusts by number screenfuls. If
number is negative then characters farther to the left
become visible; if it is positive then characters far‐
ther to the right become visible.
pathName yview ?args?
This command is used to query and change the vertical position
of the text in the widget's window. It can take any of the fol‐
lowing forms:
pathName yview
Returns a list containing two elements, both of which are
real fractions between 0 and 1. The first element gives
the position of the listbox element at the top of the
window, relative to the listbox as a whole (0.5 means it
is halfway through the listbox, for example). The second
element gives the position of the listbox element just
after the last one in the window, relative to the listbox
as a whole. These are the same values passed to scroll‐
bars via the -yscrollcommand option.
pathName yview index
Adjusts the view in the window so that the element given
by index is displayed at the top of the window.
pathName yview moveto fraction
Adjusts the view in the window so that the element given
by fraction appears at the top of the window. Fraction
is a fraction between 0 and 1; 0 indicates the first
element in the listbox, 0.33 indicates the element one-
third the way through the listbox, and so on.
pathName yview scroll number what
This command adjusts the view in the window up or down
according to number and what. Number must be an integer.
What must be either units or pages. If what is units,
the view adjusts up or down by number lines; if it is
pages then the view adjusts by number screenfuls. If
number is negative then earlier elements become visible;
if it is positive then later elements become visible.
DEFAULT BINDINGS
If the selection mode is single or browse, at most one element can be
selected in the listbox at once. In both modes, clicking button 1 on
an element selects it and deselects any other selected item. In browse
mode it is also possible to drag the selection with button 1.
If the selection mode is multiple or extended, any number of elements
may be selected at once, including discontiguous ranges. In multiple
mode, clicking button 1 on an element toggles its selection state with‐
out affecting any other elements. In extended mode, pressing button 1
on an element selects it, deselects everything else, and sets the
anchor to the element under the mouse; dragging the mouse with button
1 down extends the selection to include all the elements between the
anchor and the element under the mouse, inclusive.
Most people will probably want to use browse mode for single selections
and extended mode for multiple selections; the other modes appear to be
useful only in special situations.
The behaviour of listboxes can be changed by defining new bindings for
individual widgets. The default bindings do a grab set when button 1 is
pressed and a grab release when button 1 is released. Care must be
taken when overriding either or both of these defaults to ensure that
grabbing is consistent.
BUGS
At least one entry is required for the widget to indicate that it has
keyboard focus.
SEE ALSOoptions(9), types(9)LISTBOX(9)
