Albert-Jan Roskam wrote:
Meanwhile, I tinkered a bit more with the code. I used exec() to isolate the
event handler function. It works and it's better, but I think it could be still
better. I'm not so fond of eval() and exec().
They have their uses, but yes, it's best to avoid them unless you need
them. Let's see if we can avoid them :)
from Tkinter import *
def createWidgets(veldnamen):
root=Tk()
termenlijst = {"Naam": set(["Bill Gates", "Elvis Presley"]),
"*Postcode": set(["2600AA", "8000BB"]),
"Adres": set(["Street", "Avenue"])}
handleDeletions = {}
for veldnaam in veldnamen:
labelWidget=Label(root, text=veldnaam, takefocus=False)
labelWidget.grid()
# tcl names must start with a lowercase letter
tclName = veldnaam[0].lower() + veldnaam[1:]
content = StringVar()
entryWidget=Entry(root, name=tclName, textvariable=content)
entryWidget.grid()
exec(doHandleDeletion())
handleDeletions[entryWidget] = handleDeletion
The classic solution for callbacks is to use lambda, but of course
lambda is limited to a single expression and won't do the job here. So
what you need is a factory function that returns a new function:
handleDeletions[entryWidget] = make_deletion_handler()
and the factory itself is defined something like this:
def make_deletion_handler():
# Create a function.
def handleDeletion(event, widget=entryWidget, root=root,
termenlijst=termenlijst, content=content):
actieveVenster = root.focus_get()
actieveVensternaam = str(actieveVenster)[1:].capitalize()
if actieveVensternaam.startswith("*"):
actieveVensternaam = "*"+actieveVensternaam[1:].capitalize()
vensterinhoud = content.get().strip()
print "Name: %s -- Contents: %s" \
% (actieveVensternaam, vensterinhoud)
try:
termenlijst[actieveVensternaam].remove(vensterinhoud)
actieveVenster.delete(0, END)
print "Deleted term '%s'" % vensterinhoud
except KeyError:
print "No such term '%s'" % vensterinhoud
# And return it.
return handleDeletion
If you move the factory outside of your createWidgets function, you will
need to explicitly pass arguments entryWidget, content, etc. to the
factory. Otherwise you can nest the factory inside createWidgets, at it
will pick the variables up automatically.
Hope this helps,
--
Steven
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