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

     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.

     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.

     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.

     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

     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)