起步
django 表单中有两种字段类型可以使用选择框: choicefield 和 modelchoicefield 。
对于 choicefield 的基本使用是:
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class expenseform(forms.form):
choices = (
(11, 'credit card'),
(12, 'student loans'),
(13, 'taxes'),
(21, 'books'),
(22, 'games'),
(31, 'groceries'),
(32, 'restaurants'),
)
date = forms.datefield()
category = forms.choicefield(choices=choices)
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它能渲染出:
使用分组下拉框
还可以使用如下方式生成 <optgourp> 标签：
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class expenseform(forms.form):
choices = (
('debt', (
(11, 'credit card'),
(12, 'student loans'),
(13, 'taxes'),
)),
('entertainment', (
(21, 'books'),
(22, 'games'),
)),
('everyday', (
(31, 'groceries'),
(32, 'restaurants'),
)),
)
date = forms.datefield()
category = forms.choicefield(choices=choices)
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能够渲染为：
分组模型下拉框
如果使用的是 modelchoicefield ，那抱歉，django本身没有提供解决方案。
在 https://code.djangoproject.com/ticket/27331 中提供了一个很好的解决方案。
首先为需要分类的类型创建模型，在另一个模型中用外键关联它：
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from django.db import models
class category(models.model):
name = models.charfield(max_length=30)
parent = models.foreignkey('category', on_delete=models.cascade, null=true)
def __str__(self):
return self.name
class expense(models.model):
amount = models.decimalfield(max_digits=10, decimal_places=2)
date = models.datefield()
category = models.foreignkey(category, on_delete=models.cascade)
def __str__(self):
return self.amount
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其次，创建一个新的表单 field 类型：
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from functools import partial
from itertools import groupby
from operator import attrgetter
from django.forms.models import modelchoiceiterator, modelchoicefield
class groupedmodelchoiceiterator(modelchoiceiterator):
def __init__(self, field, groupby):
self.groupby = groupby
super().__init__(field)
def __iter__(self):
if self.field.empty_label is not none:
yield ("", self.field.empty_label)
queryset = self.queryset
# can't use iterator() when queryset uses prefetch_related()
if not queryset._prefetch_related_lookups:
queryset = queryset.iterator()
for group, objs in groupby(queryset, self.groupby):
yield (group, [self.choice(obj) for obj in objs])
class groupedmodelchoicefield(modelchoicefield):
def __init__(self, *args, choices_groupby, **kwargs):
if isinstance(choices_groupby, str):
choices_groupby = attrgetter(choices_groupby)
elif not callable(choices_groupby):
raise typeerror('choices_groupby must either be a str or a callable accepting a single argument')
self.iterator = partial(groupedmodelchoiceiterator, groupby=choices_groupby)
super().__init__(*args, **kwargs)
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最后，在表单中可以如下进行使用：
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from django import forms
from .fields import groupedmodelchoicefield
from .models import category, expense
class expenseform(forms.modelform):
category = groupedmodelchoicefield(
queryset=category.objects.exclude(parent=none),
choices_groupby='parent'
)
class meta:
model = expense
fields = ('amount', 'date', 'category')
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以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：http://www.hongweipeng.com/index.php/archives/1790/