Django ModelForm上的ForeignKey Field的自由格式输入

问题描述

我有一个外键相关的两个模型：

I have two models related by a foreign key:

# models.py
class TestSource(models.Model):
  name        = models.CharField(max_length=100)

class TestModel(models.Model):
  name        = models.CharField(max_length=100)
  attribution = models.ForeignKey(TestSource, null=True)

默认情况下，django ModelForm将呈现这作为< select> 与< option> s;然而，我希望这个函数作为一个自由的表单输入，< input type =text/> ，并在幕后获取或创建必要的TestSource对象，然后将其与TestModel对象相关联。

By default, a django ModelForm will present this as a <select> with <option>s; however I would prefer that this function as a free form input, <input type="text"/>, and behind the scenes get or create the necessary TestSource object and then relate it to the TestModel object.

我已经尝试定义一个自定义的ModelForm和Field来完成此操作：

I have tried to define a custom ModelForm and Field to accomplish this:

# forms.py
class TestField(forms.TextInput):
  def to_python(self, value):
    return TestSource.objects.get_or_create(name=value)

class TestForm(ModelForm):
  class Meta:
    model=TestModel
    widgets = {
      'attribution' : TestField(attrs={'maxlength':'100'}),
    }

不幸的是，得到： int（）的无效字面值为10：'test3'当尝试在提交表单上检查 is_valid 。我哪里错了？是否可以完成这项工作？

Unfortunately, I am getting: invalid literal for int() with base 10: 'test3' when attempting to check is_valid on the submitted form. Where am I going wrong? Is their and easier way to accomplish this?

推荐答案

这样做应该有效：

class TestForm(ModelForm):
  attribution = forms.CharField(max_length=100)

  def save(self, commit=True):
      attribution_name = self.cleaned_data['attribution']
      attribution = TestSource.objects.get_or_create(name=attribution_name)[0]  # returns (instance, <created?-boolean>)
      self.instance.attribution = attribution

      return super(TestForm, self).save(commit)

  class Meta:
    model=TestModel
    exclude = ('attribution')

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