bind
- Preface
- Introduction
- Tutorial
- Implementation
- Commands
- bitmap
- eval-wish
- get-tk-var
- photo
- set-tk-var!
- tk
- tk-id->widget
- tk-var
- tk/after
- tk/appname
- tk/bind
- tk/bindtags
- tk/caret
- tk/choosecolor
- tk/choosedirectory
- tk/clipboard
- tk/console
- tk/destroy
- tk/dialog
- tk/event
- tk/focus
- tk/getopenfile
- tk/getsavefile
- tk/grab
- tk/grid
- tk/image
- tk/lower
- tk/messagebox
- tk/option
- tk/pack
- tk/place
- tk/popup
- tk/raise
- tk/scaling
- tk/update
- tk/useinputmethods
- tk/wait
- tk/windowingsystem
- tk/winfo
- tk/wm
- Options
- Extensions
- Changes
- (#<widget> 'bind tagOrId ?sequence? ?command?)
- This command associates command with all the items given by
tagOrIdsuch that whenever the event sequence given by sequence occurs for one of the items the command will be invoked.
This widget command is similar to the tk/bind command except that it operates on items in a canvas rather than entire widgets. See the tk/bind manual entry for complete details on the syntax of sequence and the substitutions performed on command before invoking it.
If all arguments are specified then a new binding is created, replacing any existing binding for the same sequence and tagOrId (if the first element of command is + then command augments an existing binding rather than replacing it). In this case the return value is an empty string.
If command is omitted then the command returns the command associated with tagOrId and sequence (an error occurs if there is no such binding). If both command and sequence are omitted then the command returns a list of all the sequences for which bindings have been defined for tagOrId.
The only events for which bindings may be specified are those related to the mouse and keyboard (such as Enter, Leave, ButtonPress, Motion, and KeyPress) or virtual events. The handling of events in canvases uses the current item defined in item ids and tags above. Enter and Leave events trigger for an item when it becomes the current item or ceases to be the current item; note that these events are different than Enter and Leave events for windows. Mouse-related events are directed to the current item, if any. Keyboard-related events are directed to the focus item, if any (see the focus widget command below for more on this). If a virtual event is used in a binding, that binding can trigger only if the virtual event is defined by an underlying mouse-related or keyboard-related event.
It is possible for multiple bindings to match a particular event. This could occur, for example, if one binding is associated with the item's id and another is associated with one of the item's tags. When this occurs, all of the matching bindings are invoked. A binding associated with the all tag is invoked first, followed by one binding for each of the item's tags (in order), followed by a binding associated with the item's id. If there are multiple matching bindings for a single tag, then only the most specific binding is invoked.
If bindings have been created for a canvas window using the bind command, then they are invoked in addition to bindings created for the canvas's items using the bind widget command. The bindings for items will be invoked before any of the bindings for the window as a whole.