1bindtags(n) Tk Built-In Commands bindtags(n)
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8 bindtags - Determine which bindings apply to a window, and order of
9 evaluation
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12 bindtags window ?tagList?
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16 When a binding is created with the bind command, it is associated
17 either with a particular window such as .a.b.c, a class name such as
18 Button, the keyword all, or any other string. All of these forms are
19 called binding tags. Each window contains a list of binding tags that
20 determine how events are processed for the window. When an event
21 occurs in a window, it is applied to each of the window's tags in
22 order: for each tag, the most specific binding that matches the given
23 tag and event is executed. See the bind command for more information
24 on the matching process.
25 By default, each window has four binding tags consisting of the name of
27 the window, the window's class name, the name of the window's nearest
28 toplevel ancestor, and all, in that order. Toplevel windows have only
29 three tags by default, since the toplevel name is the same as that of
30 the window. The bindtags command allows the binding tags for a window
31 to be read and modified.
32 If bindtags is invoked with only one argument, then the current set of
34 binding tags for window is returned as a list. If the tagList argument
35 is specified to bindtags, then it must be a proper list; the tags for
36 window are changed to the elements of the list. The elements of
37 tagList may be arbitrary strings; however, any tag starting with a dot
38 is treated as the name of a window; if no window by that name exists
39 at the time an event is processed, then the tag is ignored for that
40 event. The order of the elements in tagList determines the order in
41 which binding scripts are executed in response to events. For example,
42 the command
43 bindtags .b {all . Button .b}
44 reverses the order in which binding scripts will be evaluated for a
45 button named .b so that all bindings are invoked first, following by
46 bindings for .b's toplevel (“.”), followed by class bindings, followed
47 by bindings for .b. If tagList is an empty list then the binding tags
48 for window are returned to the default state described above.
49 The bindtags command may be used to introduce arbitrary additional
51 binding tags for a window, or to remove standard tags. For example,
52 the command
53 bindtags .b {.b TrickyButton . all}
54 replaces the Button tag for .b with TrickyButton. This means that the
55 default widget bindings for buttons, which are associated with the But‐
56 ton tag, will no longer apply to .b, but any bindings associated with
57 TrickyButton (perhaps some new button behavior) will apply.
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60 If you have a set of nested frame widgets and you want events sent to a
61 button widget to also be delivered to all the widgets up to the current
62 toplevel (in contrast to Tk's default behavior, where events are not
63 delivered to those intermediate windows) to make it easier to have
64 accelerators that are only active for part of a window, you could use a
65 helper procedure like this to help set things up:
66 proc setupBindtagsForTreeDelivery {widget} {
67 set tags [list $widget [winfo class $widget]]
68 set w $widget
69 set t [winfo toplevel $w]
70 while {$w ne $t} {
71 set w [winfo parent $w]
72 lappend tags $w
73 }
74 lappend tags all
75 bindtags $widget $tags
76 }
77
79 bind(n)
80
82 binding, event, tag
83Tk 4.0 bindtags(n)