bindtags(n) Tk (4.0) bindtags(n)
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NAME
bindtags - Determine which bindings apply to a window, and
order of evaluation
SYNOPSIS
bindtags window ?tagList?
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DESCRIPTION
When a binding is created with the bind command, it is
associated either with a particular window such as .a.b.c, a
class name such as Button, the keyword all, or any other
string. All of these forms are called binding tags. Each
window contains a list of binding tags that determine how
events are processed for the window. When an event occurs
in a window, it is applied to each of the window's tags in
order: for each tag, the most specific binding that matches
the given tag and event is executed. See the bind command
for more information on the matching process.
By default, each window has four binding tags consisting of
the name of the window, the window's class name, the name of
the window's nearest toplevel ancestor, and all, in that
order. Toplevel windows have only three tags by default,
since the toplevel name is the same as that of the window.
The bindtags command allows the binding tags for a window to
be read and modified.
If bindtags is invoked with only one argument, then the
current set of binding tags for window is returned as a
list. If the tagList argument is specified to bindtags,
then it must be a proper list; the tags for window are
changed to the elements of the list. The elements of
tagList may be arbitrary strings; however, any tag starting
with a dot is treated as the name of a window; if no window
by that name exists at the time an event is processed, then
the tag is ignored for that event. The order of the
elements in tagList determines the order in which binding
scripts are executed in response to events. For example,
the command
bindtags .b {all . Button .b}
reverses the order in which binding scripts will be
evaluated for a button named .b so that all bindings are
invoked first, following by bindings for .b's toplevel
(``.''), followed by class bindings, followed by bindings
for .b. If tagList is an empty list then the binding tags
for window are returned to the default state described
above.
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bindtags(n) Tk (4.0) bindtags(n)
The bindtags command may be used to introduce arbitrary
additional binding tags for a window, or to remove standard
tags. For example, the command
bindtags .b {.b TrickyButton . all}
replaces the Button tag for .b with TrickyButton. This
means that the default widget bindings for buttons, which
are associated with the Button tag, will no longer apply to
.b, but any bindings associated with TrickyButton (perhaps
some new button behavior) will apply.
SEE ALSO
bind
KEYWORDS
binding, event, tag
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