Provided by: tk8.6-doc_8.6.14-1build1_all 
NAME
listbox - Create and manipulate 'listbox' item list widgets
SYNOPSIS
listbox pathName ?options?
STANDARD OPTIONS
-background -borderwidth -cursor
-disabledforeground -exportselection -font
-foreground -highlightbackground -highlightcolor
-highlightthickness -justify -relief
-selectbackground -selectborderwidth -selectforeground
-setgrid -takefocus -xscrollcommand
-yscrollcommand
See the options manual entry for details on the standard options.
WIDGET-SPECIFIC OPTIONS
Command-Line Name:-activestyle
Database Name: activeStyle
Database Class: ActiveStyle
Specifies the style in which to draw the active element. This must be one of dotbox (show a focus
ring around the active element), none (no special indication of active element) or underline
(underline the active element). The default is underline on Windows, and dotbox elsewhere.
Command-Line Name:-height
Database Name: height
Database Class: Height
Specifies the desired height for the window, in lines. If zero or less, then the desired height
for the window is made just large enough to hold all the elements in the listbox.
Command-Line Name:-listvariable
Database Name: listVariable
Database Class: Variable
Specifies the name of a global variable. The value of the variable is a list to be displayed
inside the widget; if the variable value changes then the widget will automatically update itself
to reflect the new value. Attempts to assign a variable with an invalid list value to
-listvariable will cause an error. Attempts to unset a variable in use as a -listvariable will
fail but will not generate an error.
Command-Line Name:-selectmode
Database Name: selectMode
Database Class: SelectMode
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 browse.
Command-Line Name:-state
Database Name: state
Database Class: State
Specifies one of two states for the listbox: normal or disabled. If the listbox is disabled then
items may not be inserted or deleted, items are drawn in the -disabledforeground color, and
selection cannot be modified and is not shown (though selection information is retained).
Command-Line Name:-width
Database Name: width
Database Class: Width
Specifies the desired width for the window in characters. If the font does not have a uniform
width then the width of the character “0” is used in translating from character units to screen
units. If zero or less, then the desired width for the window is made just large enough to hold
all the elements in the listbox.
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DESCRIPTION
The listbox command creates a new window (given by the pathName argument) and makes it into a listbox
widget. Additional options, described above, may be specified on the command line or in the option
database to configure aspects of the listbox such as its colors, 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, but pathName's parent must exist.
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. If a listbox is exporting its selection (see
-exportselection option), then it will observe the standard X11 protocols for handling the selection.
Listbox selections are available as type STRING; the value of the selection will be the text of the
selected elements, with newlines separating the elements.
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. They also support scanning,
as described below.
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 corresponds to the first element in the
listbox.
active Indicates the element that has the location cursor. This element will be displayed as
specified by -activestyle 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 most commands this refers to the last element in the
listbox, but for a few commands such as index and insert it refers to the element just after
the last one.
@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 Tcl 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 behavior of the command. The following commands are possible for
listbox widgets:
pathName activate index
Sets the active element to the one indicated by index. If index is outside the range of elements
in the listbox then the closest element is activated. The active element is drawn as specified by
-activestyle when the widget has the input focus, and its index may be retrieved with the index
active.
pathName bbox index
Returns a list of four numbers describing the bounding box of the text in the element given by
index. The first two elements of the list give the x and y coordinates of the upper-left corner
of the screen area covered by the text (specified in pixels relative to the widget) and the last
two elements give the width and height of the area, in pixels. If no part of the element given by
index is visible on the screen, or if index refers to a non-existent element, then the result is
an empty string; if the element is partially visible, the result gives the full area of the
element, including any parts that are not visible.
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.
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no option is specified, returns a
list describing all of the available options for pathName (see Tk_ConfigureInfo for information on
the format of this list). If option is specified with no value, then the command returns a list
describing the one named option (this list will be identical to the corresponding sublist of the
value returned if no option is specified). 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 is not 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, or an empty
string if first refers to a non-existent element. 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 the integer index value that corresponds to index. If index is end the return value is a
count of the number of elements in the listbox (not the index of the last element).
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 itemcget index option
Returns the current value of the item configuration option given by option. Option may have any of
the values accepted by the itemconfigure command.
pathName itemconfigure index ?option? ?value? ?option value ...?
Query or modify the configuration options of an item in the listbox. If no option is specified,
returns a list describing all of the available options for the item (see Tk_ConfigureInfo for
information on the format of this list). If option is specified with no value, then the command
returns a list describing the one named option (this list will be identical to the corresponding
sublist of the value returned if no option is specified). 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. The following options are currently supported for
items:
-background color
Color specifies the background color to use when displaying the item. It may have any of
the forms accepted by Tk_GetColor.
-foreground color
Color specifies the foreground color to use when displaying the item. It may have any of
the forms accepted by Tk_GetColor.
-selectbackground color
color specifies the background color to use when displaying the item while it is selected.
It may have any of the forms accepted by Tk_GetColor.
-selectforeground color
color specifies the foreground color to use when displaying the item while it is selected.
It may have any of the forms accepted by Tk_GetColor.
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 scan option args
This command is used to implement scanning on listboxes. It has two forms, depending on option:
pathName scan mark x y
Records x and y and the current view in the listbox window; used in conjunction with later
scan dragto commands. Typically this command is associated with a mouse button press in
the widget. It returns an empty string.
pathName scan dragto x y.
This command computes the difference between its x and y arguments and the x and y
arguments to the last scan mark command for the widget. It then adjusts the view by 10
times the difference in coordinates. This command is typically associated with mouse
motion events in the widget, to produce the effect of dragging the list at high speed
through the window. The return value is an empty string.
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.
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. If index refers to a non-existent
element, then the closest element is used. 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 is not.
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 element 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
-xscrollcommand 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 or an abbreviation of one of
these. 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 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
Tk automatically creates class bindings for listboxes that give them Motif-like behavior. Much of the
behavior of a listbox is determined by its -selectmode option, which selects one of four ways of dealing
with the selection.
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. On button 1, the listbox will also
take focus if it has a normal state.
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 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.
Any time the set of selected item(s) in the listbox is updated by the user through the keyboard or mouse,
the virtual event <<ListboxSelect>> will be generated. This virtual event will not be generated when
adjusting the selection with the pathName selection command. It is easiest to bind to this event to be
made aware of any user changes to listbox selection.
In addition to the above behavior, the following additional behavior is defined by the default bindings:
[1] In extended mode, the selected range can be adjusted by pressing button 1 with the Shift key down:
this modifies the selection to consist of the elements between the anchor and the element under
the mouse, inclusive. The un-anchored end of this new selection can also be dragged with the
button down.
[2] In extended mode, pressing button 1 with the Control key down starts a toggle operation: the
anchor is set to the element under the mouse, and its selection state is reversed. The selection
state of other elements is not changed. If the mouse is dragged with button 1 down, then the
selection state of all elements between the anchor and the element under the mouse is set to match
that of the anchor element; the selection state of all other elements remains what it was before
the toggle operation began.
[3] If the mouse leaves the listbox window with button 1 down, the window scrolls away from the mouse,
making information visible that used to be off-screen on the side of the mouse. The scrolling
continues until the mouse re-enters the window, the button is released, or the end of the listbox
is reached.
[4] Mouse button 2 may be used for scanning. If it is pressed and dragged over the listbox, the
contents of the listbox drag at high speed in the direction the mouse moves.
[5] If the Up or Down key is pressed, the location cursor (active element) moves up or down one
element. If the selection mode is browse or extended then the new active element is also selected
and all other elements are deselected. In extended mode the new active element becomes the
selection anchor.
[6] In extended mode, Shift-Up and Shift-Down move the location cursor (active element) up or down one
element and also extend the selection to that element in a fashion similar to dragging with mouse
button 1.
[7] The Left and Right keys scroll the listbox view left and right by the width of the character 0.
Control-Left and Control-Right scroll the listbox view left and right by the width of the window.
Control-Prior and Control-Next also scroll left and right by the width of the window.
[8] The Prior and Next keys scroll the listbox view up and down by one page (the height of the
window).
[9] The Home and End keys scroll the listbox horizontally to the left and right edges, respectively.
[10] Control-Home sets the location cursor to the first element in the listbox, selects that element,
and deselects everything else in the listbox.
[11] Control-End sets the location cursor to the last element in the listbox, selects that element, and
deselects everything else in the listbox.
[12] In extended mode, Control-Shift-Home extends the selection to the first element in the listbox and
Control-Shift-End extends the selection to the last element.
[13] In multiple mode, Control-Shift-Home moves the location cursor to the first element in the listbox
and Control-Shift-End moves the location cursor to the last element.
[14] The space and Select keys make a selection at the location cursor (active element) just as if
mouse button 1 had been pressed over this element.
[15] In extended mode, Control-Shift-space and Shift-Select extend the selection to the active element
just as if button 1 had been pressed with the Shift key down.
[16] In extended mode, the Escape key cancels the most recent selection and restores all the elements
in the selected range to their previous selection state.
[17] Control-slash selects everything in the widget, except in single and browse modes, in which case
it selects the active element and deselects everything else.
[18] Control-backslash deselects everything in the widget, except in browse mode where it has no
effect.
[19] The F16 key (labelled Copy on many Sun workstations) or Meta-w copies the selection in the widget
to the clipboard, if there is a selection.
The behavior of listboxes can be changed by defining new bindings for individual widgets or by redefining
the class bindings.
SEE ALSO
ttk::treeview(3tk)
KEYWORDS
listbox, widget
Tk 8.4 listbox(3tk)