I am fairly new and using Django Admin to manage a set of lists and
forms for a database GUI.
I am not happy with the performance rendering a form which has
foreignkey fields or manytomany fields with numerous values. This
inspired me to get involved with overloading
"formfield_for_foreignkey" which I eventually managed.
When I went to tackle a "manytomany" formfield for an 'inline' the
"admin" doco says "use 'formfield_for_manytomany' as usual, so I
created the approriate method in the 'inline' Class but it was never
invoked.
Numerous clever workarounds are given in the forums but I decided to
try using "formfield_for_manytomany" in the inline class. This works
brilliantly.
I guess the principle is that within the "through" model, the fields
are actually "foreignkey" fields, and the 'db_field.name' values
correspond to that model.
Here is a fragment of code where I cache the queryset for multiple
fields in the session dictionary.
#---------------------------------------------
# use inline feature in Route for Points and Tracks
class PointsInline(TabularInline):
model = Route.points.through
extra = 0
class TracksInline(TabularInline):
def formfield_for_foreignkey( self,db_field, request, **kwargs):
if db_field.name == "track_id" or db_field.name == "point_id":
url_split = request.path.split('/')
route_id = url_split[-2]
try:
previous_id = request.session.get("RouteId")
except:
previous_id = None
if route_id <> previous_id :
print db_field.name, request.path, "\n"
request.session["RouteId"] = route_id
q_line =
Route.objects.get(id=route_id).from_signal.location.line
tq_set = Track.objects.filter(location__line=q_line)
request.session["TrackList"] = tq_set
pq_set = Point.objects.filter(location__line=q_line)
request.session["PointList"] = pq_set
print q_line, tq_set.count(), pq_set.count()
if db_field.name == "track_id":
q_set = request.session["TrackList"]
else:
q_set = request.session["PointList"]
kwargs["queryset"] = q_set
return super(TracksInline,
self).formfield_for_foreignkey(db_field, request, **kwargs )
else:
return None
model = Route.tracks.through
extra = 0
class RouteAdmin(ModelAdmin):
inlines = [ PointsInline, TracksInline ]
list_per_page = 48
list_display =
('__unicode__','from_signal','to_signal','direction')
list_filter= ('to_signal__location__line',)
exclude = ('tracks','points',)
search_fields =
('to_signal__location__vcode','from_signal__location__vcode',)
#---------------------------------------------
--
You received this message because you are subscribed to the Google Groups
"Django users" group.
To post to this group, send email to django-users@googlegroups.com.
To unsubscribe from this group, send email to
django-users+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/django-users?hl=en.
