向Django Admin添加字段总和的行

Question

我有一个发票应用程序，我希望能够在底部的管理面板中显示发票的总额。(我使用的是Django-suit)

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在Django中有没有一种简单的方法来做到这一点？

e:像这样的东西应该起作用吗？

class InvoiceAdmin(admin.ModelAdmin):
    inlines = [InvoiceItemInline]
    list_display = ('description', 'date', 'status', 'invoice_amount')

    def invoice_amount(self, request):
        amount = InvoiceItem.objects.filter(invoice__id=request.id).values_list('price', flat=True)
        quantity = InvoiceItem.objects.filter(invoice__id=request.id).values_list('quantity', flat=True)
        total_current = amount(float) * quantity(float)
        total_amount = sum(total_current)
        return total_amount

Answer 1

除了list_display仅适用于列出所有发票的页面之外，您的思路是正确的，在编辑特定发票时，您将看不到这一点

要在编辑特定发票时查看它，我认为您需要覆盖change_view方法，该方法被称为视图函数：

https://docs.djangoproject.com/en/1.7/ref/contrib/admin/#django.contrib.admin.ModelAdmin.change_view

如下所示：

class InvoiceAdmin(admin.ModelAdmin):
    inlines = [InvoiceItemInline]
    list_display = ('description', 'date', 'status', 'invoice_amount')

    # You need to customise the template to make use of the new context var
    change_form_template = 'admin/myapp/extras/mymodelname_change_form.html'

    def _invoice_amount(self, invoice_id):
        # define our own method to serve both cases
        order_values = InvoiceItem.objects.filter(invoice__id=invoice_id).values_list(
            'price', 'quantity', flat=True)
        return reduce(
            lambda total, (price, qty): total + (price * qty),
            order_values,
            0
        )

    def invoice_amount(self, instance):
        # provides order totals for invoices list view
        return self._invoice_amount(instance.pk)

    def change_view(self, request, object_id, form_url='', extra_context=None):
        # provides order total on invoice change view
        extra_context = extra_context or {}
        extra_context['order_total'] = self._invoice_amount(object_id)
        return super(MyModelAdmin, self).change_view(request, object_id,
            form_url, extra_context=extra_context)

注意，您还需要覆盖变更表单模板，以利用我们在extra_context中传回的order_total变量