我想根据max_digits和decimal_places属性自动绕Django的十分位域围绕Decimalfield,然后在modelform中调用Save Save()函数。
>当前使用以下内容:
- django 1.8
- Python 2.7
我到目前为止尝试过的。
https://djangosnippets.org/snippets/10554/
models.py
amount = models.DecimalField(max_digits = 19, decimal_places = 2)
views.py
P.S。将其应用于不同的领域和不同的模型
data = {"amount" : 100.1234,"name":"John Doe",...}
form = My_form(data)
if form.is_valid(): //the error throws from here.
form.save()
else:
raise ValueError(form.errors)
forms.py
我计划在清洁()函数中清洁字段,并在所有小数区域中进行舍入,但是当我尝试打印RAW_DATA时,没有"金额"字段。
class My_form(forms.ModelForm):
Class Meta:
model = My_model
fields = ('amount','name')
def clean(self):
raw_data = self.cleaned_data
print(raw_data) //only prints {'name' : 'John Doe'}
您主要遇到错误,因为forms.DecimalField
具有 models.DecimalField
的单独验证器:
data = {'amount': 1.12345 }
class NormalForm(forms.Form):
amount = forms.DecimalField(max_digits = 19, decimal_places = 2)
normal_form = NormalForm(data)
normal_form.is_valid() # returns False
normal_form.cleaned_data # returns {}
和 forms.DecimalField
默认用于具有models.DecimalField
类字段的模型的表单。您可以做这样的事情:
from django import forms
from django.db import models
from decimal import Decimal
def round_decimal(value, places):
if value is not None:
# see https://docs.python.org/2/library/decimal.html#decimal.Decimal.quantize for options
return value.quantize(Decimal(10) ** -places)
return value
class RoundingDecimalFormField(forms.DecimalField):
def to_python(self, value):
value = super(RoundingDecimalFormField, self).to_python(value)
return round_decimal(value, self.decimal_places)
class RoundingDecimalModelField(models.DecimalField):
def to_python(self, value):
# you could actually skip implementing this
value = super(RoundingDecimalModelField, self).to_python(value)
return round_decimal(value, self.decimal_places)
def formfield(self, **kwargs):
defaults = { 'form_class': RoundingDecimalFormField }
defaults.update(kwargs)
return super(RoundingDecimalModelField, self).formfield(**kwargs)
现在您使用models.DecimalField
的任何地方,而是使用RoundingDecimalModelField
。您与这些型号一起使用的任何表单现在也将使用自定义表单字段。
class RoundingForm(forms.Form):
amount = RoundingDecimalFormField(max_digits = 19, decimal_places = 2)
data = {'amount': 1.12345 }
rounding_form = RoundingForm(data)
rounding_form.is_valid() # returns True
rounding_form.cleaned_data # returns {'amount': Decimal('1.12')}
如果您直接分配给模型实例,则无需担心它。字段对象将将值(将其舍入)量化为您在模型定义中设置的小数点级别。
如果您要处理ModelForm
,则默认的DecimalField
将要求任何输入匹配模型字段的小数点。一般而言,处理此问题的最简单方法可能是将模型DecimalField
分类,删除小数点特定的验证器并依靠基础转换来量化数据:
from django.db.models.fields import DecimalField
class RoundingDecimalField(DecimalField):
@cached_property
def validators(self):
return super(DecimalField, self).validators
def formfield(self, **kwargs):
defaults = {
'max_digits': self.max_digits,
'decimal_places': 4, # or whatever number of decimal places you want your form to accept, make it a param if you like
'form_class': forms.DecimalField,
}
defaults.update(kwargs)
return super(RoundingDecimalField, self).formfield(**defaults)
然后在您的模型中:
amount = RoundingDecimalField(max_digits = 19, decimal_places = 2)
(实际上并没有将字段类放在与模型同一字段中,例如。)
这在绝对方面可能不太正确,而不是定义自定义字段表格,这是我的第一个建议,但使用的工作较少。
如果要设置窗口小部件以限制小数号输入表单呈现,则只需使用此代码
from django import forms
class DecimalNumberInput(forms.NumberInput):
def get_context(self, name, value, attrs):
context = super().get_context(name, value, attrs)
try:
if self.attrs['decimal_places'] and isinstance(self.attrs['decimal_places'], int) :
context['widget']['value'] = str(round(float(context['widget']['value']),self.attrs['decimal_places']))
except Exception as e:
pass
return context
class NormalForm(forms.Form):
amount = forms.DecimalField(max_digits = 19, decimal_places = 2 , widget=DecimalNumberInput(attrs={'decimal_places':2}))