Changing max_length on a CharField for a ModelForm

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I have defined the max_length on a field to be 50 in the model definition. When a form is created it takes those attributes to make the fields, but I would like to overwrite that max_length for that specific form without changing the model itself.

This is what I have in my model

text_field01 = models.CharField(max_length=50, default="")
text_field02 = models.CharField(max_length=50, default="")

I tried overwriting the widget with a new widget in my forms.py but that threw an error. I also tried it in the init but that seemed to have no effect. I am a bit stuck, any help would be greatly appreciated.

EDIT

At first I tried setting the widgets in class meta as shown below.

widgets = {
'text_field01': forms.CharField(max_length=10)

This produced an error "CharField" object has no attribute 'is_hidden'

Then I tried doing it in init as shown below.

        def __init__(self, *args, **kwargs):
            super(AutomationForm, self).__init__(data=data, files=files, *args, **kwargs)
            if self.instance:
                if self.fields['text_field01']:
                    self.fields['text_field01'].max_length = 2

Which simply had no effect.

python-3.x django-forms django
1 Answers

You can create a ModelForm, and override the value for the max_length=… parameter [Django-doc]:

class MyModelForm(forms.ModelForm):
    text_field01 = forms.CharField(max_length=25)

    class Meta:
        model = MyModel
        fields = '__all__'

The max_length you define in the ModelForm can only be less than or equal to the one in the Model itself, since validation in the model has to succeed as well.

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