django - django-tables2 中的非查询集数据排序

Question

文档说:

Where the table is backed by a model, the database will handle the ordering. Where this is not the case, the Python cmp function is used and the following mechanism is used as a fallback when comparing across different types: ...

但是，在由模型支持的表(在自定义列上)中，这可能吗？例如

class MyModel(models.Model):
    x = models.IntegerField()
    y = models.IntegerField()

    def z(self):
        return x+y

class MyTable(tables.Table):
    z = tables.Column()
    class Meta:
        model = MyModel

当我尝试类似的操作时，该列显示“正常”，但是当我单击列标题进行排序时，出现此错误:

Caught FieldError while rendering: Cannot resolve keyword u'z' into field. Choices are: ...

显然这是因为在数据库表中找不到 z。

有办法解决这个问题吗？

Answer 1

如果您对没有数据库列的属性进行排序，则无法使用查询集。不过，您可以将列表传递到您的表。

假设您的 models.py 如下所示:

from django.db import models

class MyModel(models.Model):
    def foo(self):
        return something_complex()

你可以有如下所示的tables.py:

import django_tables2 as tables
from .models import MyModel

class MyModelTable(tables.Table):
    foo = tables.Column()

    class Meta:
        model = MyModel

然后在你的views.py中:

from django_tables2.config import RequestConfig
from django.core.paginator import InvalidPage
from django.shortcuts import render

def view_my_models(request):
    # use a list so django_tables2 sorts in memory
    my_models = list(MyModel.objects.all())

    my_models_table = MyModelTable(my_models)
    RequestConfig(request).configure(my_models_table)

    try:
        page_number = int(request.GET.get('page'))
    except (ValueError, TypeError):
        page_number = 1

    try:
        my_models_table.paginate(page=page_number, per_page=10)
    except InvalidPage:
        my_models_table.paginate(page=1, per_page=10)

    template_vars = {'table': my_models_table}
    return render(response, "view_my_models.html", template_vars)

还有an open ticket discussing this issue .