Tkinter.event.widget: handler gets name instead of widget.
tjreedy at udel.edu
Mon Jul 9 07:58:48 CEST 2012
On 7/8/2012 5:19 PM, Frederic Rentsch wrote:
> Hi widget wizards,
> The manual describes the "event" attribute "widget" as "The widget
> which generated this event. This is a valid Tkinter widget instance, not
> a name. This attribute is set for all events."
Same in 3.3, with nice example of using it.
def turnRed(self, event):
event.widget["activeforeground"] = "red"
> Ans so it is--has been until on the latest occasion "event.widget" was
> not the widget, but its name, crashing the handler.
Has event.widget been the widget only in other programs or previously
with the same program?
> # Here I build a list of selectable records having each four fields.
> # The fields are labels. The selectable line is a frame containing the
> # labels side by side. The line frames go into self, which is a Frame.
> for n in range (len (records)):
for n, record in enumerate(records):
> record = records [n]
> line_frame = Frame (self, name = '-%d-' % n, relief = RAISED, **BUTTON_FRAME_)
> line_frame.bind ('<Enter>', self.enter)
> line_frame.bind ('<Leave>', self.leave)
> line_frame.bind ('<ButtonRelease-1>', self.pick_record)
> line_frame.bind ('<ButtonRelease-3>', self.info_profile)
> line_frame.grid (row = n+2, column = 1)
> for i in self.range_n_fields: # (0, 1, 2, 3)
> field = Label (line_frame, text = record [self.INDICES [i]], anchor = W, width = self.COLUMN_WIDTHS [i], **DB_LIST_LABEL_)
> field.grid (row = 0, column = i, sticky = NW)
When posting problem code, you should post a minimal, self-contained
example that people can try on other systems and versions. Can you
create the problem with one record, which you could give, and one
binding? Do you need 4 fields, or would 1 'work'?
> # Here is the <Enter> handler:
> def enter (self, event):
> w = event.widget
> print 'hit list.enter (). Event, widget', event, w, w.__class__ # Tracing line
> w.config (bg = SELECTED_BG_COLOR)
> # And here is what comes out. The first line is my tracing line. The name is correct in that it
> # names the entered line_frame, but is wrong because it should be the line_frame, not its name.
> # The rest is the red exception message:
> hit list.enter (). Event, widget <Tkinter.Event instance at 0x9115dcc> .main-frame.data-frame.title-hit-list.-10- <type 'str'>
> Exception in Tkinter callback
> Traceback (most recent call last):
> File "/usr/lib/python2.6/lib-tk/Tkinter.py", line 1413, in __call__
> return self.func(*args)
> File "/home/fr/python/finance/piam/hit_list.py", line 83, in enter
> w.config (bg = SELECTABLE_BG_COLOR)
> AttributeError: 'str' object has no attribute 'config'
> # The same thing happens with <Leave>. The other handlers I haven't done yet. The same bindings work well in
> # a Menu class with the difference that the bindings are on the Labels, not a containing Frame.
> # Dell E6500, Ubuntu 10.04, Python 2.6
You might try a current Python release, and the latest tcl/tk 8.5.11
released last March (comes with 3.3.0 Windows release, don't know how on
Ubuntu). There might be (have been?) a bug with events on Frames, or on
Frames within Frames treated as widgets.
Terry Jan Reedy
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