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

@Yuji 'Tomita' Tomitayou the idea was good, i had the same but once trying, i realized you must also remove specific key from self.inlines because in change_view and add_view method self.get_inline_instances(request) is called before get_formsets(). Therefore i moved inlines handling to get_form() method.

Here is how i sucessfully did it:

class SampleAdmin(ModelAdmin):
    inlines = []

    def get_inlines(self):
        return [SampleInline, SampleInline2]

    def get_form(self, request, obj=None, **kwargs):
        # due to django admin form fields caching you must 
        # redefine inlines on every `get_form()` call
        if (obj): self.inlines = self.get_inlines()
        for inline in self.inlines:
            # Here change condition based on your needs and manipulate
            # self.inlines as you like (remove, change, etc). 
            # I used inline.__name__ to detect if this is correct inline 
            # for my obj
            if obj.CONDITION:
                self.inlines.remove(inline)
        return super(SampleAdmin, self).get_form(request, obj, **kwargs)