gistfile1.py

class MatchForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(MatchForm, self).__init__(*args, **kwargs)
        q = Q(closed=False, lft=F('rgt')-1)
        if self.instance.eventobj != None:
            q = q | Q(id=self.instance.eventobj.id)
        self.fields['eventobj'].queryset = Event.objects.filter(q).order_by('-id')

class MessagesInline(admin.StackedInline):
    model = Message
    fields = ['type', 'title', 'text']
    extra = 1

class MatchAdmin(admin.ModelAdmin):
    list_display = ('date', 'get_res', match_period, 'treated', 'offline', 'game', 'eventobj', 'submitter')
    exclude = ('eventobj',)
    inlines = [MessagesInline]
    form = MatchForm

    def get_res(self, obj):
        return '%s %i-%i %s' % (str(obj.pla), obj.sca, obj.scb, str(obj.plb))
    get_res.short_description = 'Result'