Limit Maximum Choices of ManyToManyField

Question

I\'m trying to limit the maximum amount of choices a model record can have in a ManyToManyField.

In this example there is a BlogSite that can be related to Regions. In t

Answer 1

Working! I have used this and its working properly. Validation required before saving the data. So you can use code in form

class BlogSiteForm(forms.ModelForm):
    def clean_regions(self):
        regions = self.cleaned_data['regions']
        if len(regions) > 3:
            raise forms.ValidationError('You can add maximum 3 regions')
        return regions
    class Meta:
        model = BlogSite
        fields = '__all__'