LISTBOX(9) LISTBOX(9)
NAME
listbox - Create and manipulate listbox widgets
SYNOPSIS
listbox 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 bindings 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 path-
Name argument) and makes it into a listbox widget. Addi-
tional 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 ele-
ments. Elements may be added or deleted using widget com-
mands 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 -xscrollcom-
mand and -yscrollcommand options.
INDICES
Many of the widget commands for listboxes take one or more
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LISTBOX(9) LISTBOX(9)
indices as arguments. An index specifies a particular ele-
ment of the listbox, in any of the following ways:
number Specifies the element as a numerical index,
where 0 corresponds to the first element in the
listbox.
active Indicates the element that has the location cur-
sor. 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 com-
mands 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 opera-
tions 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 listbox command.
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LISTBOX(9) LISTBOX(9)
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the wid-
get. 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 mod-
ifies 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 speci-
fied 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 ele-
ment 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 element.
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LISTBOX(9) LISTBOX(9)
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 ele-
ment 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 element is .6, 20% of the
listbox's text is off-screen to the left, the mid-
dle 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 -xscroll-
command option.
pathName xview index
Adjusts the view in the window so that the charac-
ter position given by index is displayed at the
left edge of the window. Character positions are
defined by the width of the character 0.
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LISTBOX(9) LISTBOX(9)
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
farther 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 following 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 scrollbars 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 win-
dow.
pathName yview moveto fraction
Adjusts the view in the window so that the element
given by fraction appears at the top of the win-
dow. 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
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LISTBOX(9) LISTBOX(9)
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 nega-
tive 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 ele-
ment 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 without affecting any other ele-
ments. 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 ele-
ments 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 ALSO
options(9), types(9)
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