我一直试图使我的django表单的外键只读，我正在创建一个网络应用程序与系统控制，我不希望某些用户编辑提交的字段

class ApproveForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(ApproveForm, self).__init__(*args, **kwargs)
        # Filter the queryset for the 'category' field to only include active categories
        self.fields['category'].queryset = Category.objects.filter(status='active')

        # Filter the queryset for the 'category' field to only include active categories
        self.fields['location'].queryset = Location.objects.filter(status='active')

        self.fields['location'].widget.attrs['readonly'] = True    


    class Meta:
        model = Request
        fields = ('item','category','location','quantity','comments' )

        widgets = {
            'item':forms.Select(attrs={
                'class':'form-control', 
            }),
            'category':forms.Select(attrs={
                'class':'form-control',
            }),
             'location':forms.Select(attrs={
                'class':'form-control',
            }),
            'quantity':forms.NumberInput(attrs={
                'class':'form-control', 'min':'0', 'readonly':'readonly'
            }),
            'comments': forms.Textarea(attrs={
                'rows':4,'cols':5, 'class':'form-control'
            })

        }

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它不工作，我已经尝试使用隐藏，它隐藏了所有的整体价值观离开标签显示