How to show different inlines depending of current object field value

Question

Given a model named MainModel and a RelatedModel, where the later has a ForeignKey field to MainModel:

class          


        

Answer 1

This worked for me while searching for an answer to the same problem in this old post. Expanding upon darklow's answer , I think you can simply override get_inline_instances completely and add an extra check based on your type.

1. Add a boolean type check method in your model

   class MainModel(models.Model):
   
       name = models.CharField(max_length=50)
   
       type = models.BooleanField()
   
       def is_type1(self):
   
          return type=="some value"
   
       def is_type2(self):
           return type=="some value"
   

2. Add inline instance base on type check - Simply copy and paste the get_inline_insances method from the parent class into your admin.ModelAdmin class and add the if block to check the model type as shown below

   class MyModelAdmin(admin.ModelAdmin):
   
       inlines = [RelatedModel1, RelatedModel2]
   
       def get_inline_instances(self, request, obj=None):
           inline_instances = []
           if not obj:
               return []
           for inline_class in self.inlines:
               inline = inline_class(self.model, self.admin_site)
               if request:
                   if not (inline.has_add_permission(request) or
                               inline.has_change_permission(request, obj) or
                               inline.has_delete_permission(request, obj)):
                       continue
                   if not inline.has_add_permission(request):
                       inline.max_num = 0
               if obj.is_type1() and isinstance(inline,RelatedModel1InlineAdmin):
                   inline_instances.append(inline)
               if obj.is_type2() and isinstance(inline,RelatedModel2InlineAdmin):
                   inline_instances.append(inline)
   
           return inline_instances