Fixing Django Model Methods for Admin Configuration

The error you're encountering is because you're trying to use model field instances (self.numero, self.nome_razao_social, etc.) in your custom methods, but these are DeferredAttribute objects, not strings. For admin configuration like list_display, Django expects field names as strings.

The Problem

In your custom methods, you're returning the actual field attributes instead of their names:

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def __list_display__(self) -> tuple:
    return (self.numero,
            self.nome_razao_social,
            self.url)

Solution

Here's how to fix your model methods:

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class Banco(models.Model):
    numero = PositiveSmallIntegerField(db_column='Numero', verbose_name='Número', primary_key=True)
    nome_razao_social = CharField(db_column='NomeRazaoSocial', verbose_name='Razão Social', max_length=100)
    url = models.CharField(db_column='URL', max_length=100, verbose_name='URL', blank=True, null=True)

    # Metadata
    class Meta:
        db_table = 'tb_bancos'
        verbose_name = 'Banco'
        verbose_name_plural = 'Bancos'
        db_table_comment = 'Cadastro de bancos'
        ordering = ['numero']

    def __str__(self):
        return self.nome_razao_social

    @classmethod
    def get_list_display(cls):
        return ('numero', 'nome_razao_social', 'url')

    @classmethod
    def get_search_fields(cls):
        return ('nome_razao_social',)

    @classmethod
    def get_list_filter(cls):
        return ('nome_razao_social',)

And here's how to fix your admin registration:

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from django.contrib import admin
from .models import Banco

@admin.register(Banco)
class BancoAdmin(admin.ModelAdmin):
    list_display = Banco.get_list_display()
    search_fields = Banco.get_search_fields()
    list_filter = Banco.get_list_filter()

Key Changes:

1. Changed the methods to use @classmethod since they don't need instance data
2. Renamed methods to follow Python conventions (no double underscores)
3. Return strings of field names instead of field instances
4. Simplified the admin registration code to avoid using eval()
5. Created a specific admin class for the Banco model

If you need to register multiple models dynamically, you can use a more structured approach:

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from django.contrib import admin
from .models import Banco

models_to_register = [Banco]  # Add more models as needed

for model in models_to_register:
    @admin.register(model)
    class DynamicAdmin(admin.ModelAdmin):
        list_display = model.get_list_display()
        search_fields = model.get_search_fields()
        list_filter = model.get_list_filter()
        
        class Meta:
            model = model

This approach is safer than using eval() and provides better type checking.