CODEWITHSUNDEEP
djangopython-2.7django-modelsdjango-admin
Shade
Shade

Reputation: 10011

Get value of field from referenced model displayed in Django Admin site

I have two models - Contract and Supplier. Each supplier supplies a type of commodity. These are defined as follows:

class CommodityType(models.Model):
    name = models.CharField(max_length=64)

    def __unicode__(self):
        return self.name

class Supplier(models.Model):
    name = models.CharField(max_length=64)
    type = models.ForeignKey(CommodityType)

    def __unicode__(self):
        return self.name

    class Meta:
        ordering = ['type', 'name']

class Contract(models.Model):
    supplier = models.ForeignKey(Supplier)
    clientNumber = models.CharField(max_length=32)

    def __unicode__(self):
        return u'%s, %s' % (self.supplier, self.clientNumber)

I want to have a listing of the Contracts in the Django Admin site. For each of the Contracts, I want to have the type from the referenced Supplier displayed. So, for example, if the associated supplier supplies Electricity, then I want to have that displayed in the listing of Contracts.

However, I cannot seem to find how this is done. I found this answer, but trying that gives me an ImproperlyConfigured error.

How can this be done?

Upvotes: 1

Views: 1652

Answers (2)

Javad
Javad

Reputation: 2098

Recently, a library called django-related-admin released, which allows you to use foreign key attributes in Django admin change list list_display with '__' so easily, Specifically for this question, how to use this library in admin.py module is as follows:

admin.py

from related_admin import RelatedFieldAdmin
from related_admin import getter_for_related_field

class ContractAdmin(RelatedFieldAdmin):
    # these fields will work automatically (and boolean fields will display an icon):
    list_display = ('clientNumber','supplier__type__name')

    # or you can also define them manually if you need to override short_description or boolean parameter:
    supplierType = getter_for_related_field('supplier__type__name', short_description='supplier type', boolean=False)

Upvotes: 0

karthikr
karthikr

Reputation: 99660

What you probably need is the list_display 

class ContractAdmin(admin.ModelAdmin):
    list_display('clientNumber', 'supplier')

admin.register(Contract, ContractAdmin)

To allow __ in Admin for foreign key, You can use this snippet

From the snippet:

from django.contrib import admin
from django.db import models

def getter_for_related_field(name, admin_order_field=None, short_description=None):
    """
        Create a function that can be attached to a ModelAdmin to use as a list_display field, e.g:
        client__name = getter_for_related_field('client__name', short_description='Client')
    """
    related_names = name.split('__')
    def getter(self, obj):
        for related_name in related_names:
            obj = getattr(obj, related_name)
        return obj
    getter.admin_order_field = admin_order_field or name
    getter.short_description = short_description or related_names[-1].title().replace('_',' ')
    return getter

class RelatedFieldAdminMetaclass(admin.ModelAdmin.__metaclass__):
    """
        Metaclass used by RelatedFieldAdmin to handle fetching of related field values.
        We have to do this as a metaclass because Django checks that list_display fields are supported by the class.
    """
    def __getattr__(self, name):
        if '__' in name:
            getter = getter_for_related_field(name)
            setattr(self, name, getter) # cache so we don't have to do this again
            return getter
        raise AttributeError # let missing attribute be handled normally

class RelatedFieldAdmin(admin.ModelAdmin):
    """
        Version of ModelAdmin that can use related fields in list_display, e.g.:
        list_display = ('address__city', 'address__country__country_code')
    """
    __metaclass__ = RelatedFieldAdminMetaclass
    def queryset(self, request):
        qs = super(RelatedFieldAdmin, self).queryset(request)

        # include all related fields in queryset
        select_related = [field.rsplit('__',1)[0] for field in self.list_display if '__' in field]

        # Include all foreign key fields in queryset.
        # This is based on ChangeList.get_query_set().
        # We have to duplicate it here because select_related() only works once.
        # Can't just use list_select_related because we might have multiple__depth__fields it won't follow.
        model = qs.model
        for field_name in self.list_display:
            try:
                field = model._meta.get_field(field_name)
            except models.FieldDoesNotExist:
                continue
            if isinstance(field.rel, models.ManyToOneRel):
                select_related.append(field_name)

        return qs.select_related(*select_related)





#### USAGE ####
class FooAdmin(RelatedFieldAdmin):
    # these fields will work automatically:
    list_display = ('address__phone','address__country__country_code','address__foo')

    # ... but you can also define them manually if you need to override short_description:
    address__foo = getter_for_related_field('address__foo', short_description='Custom Name')

Upvotes: 1

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