Working with extra fields in an Inline form - save_model, save_formset, can't make sense of the difference

Question

Suppose I am in the usual situation where there\'re extra fields in the many2many relationship:

class Person(models.Model):
    name = models.CharField(max_l         


        

Answer 1

As syn points out in his answer, for TabularInline and StackedInline, you have to override the save_formset method inside the ModelAdmin that contains the inlines.

GroupAdmin(admin.ModelAdmin):
    model = Group
    ....
    inlines = (MembershipInline,)

    def save_formset(self, request, form, formset, change):
        instances = formset.save(commit=False)

        for instance in instances:
            if isinstance(instance, Member): #Check if it is the correct type of inline
                if(not instance.author):
                    instance.author = request.user
                else:
                    instance.modified_by = request.user            
                instance.save()

Answer 2

I just hit this same problem, and it seems the solution is that for both save_formset and save_model with inlines, they are not called. Instead you must implement it in the formset which is being called which is the parent e.g.

model = Group
    ....
    inlines = (MembershipInline,)

    def save_formset(self, request, form, formset, change):
        instances = formset.save(commit=False)

        for instance in instances:
            # Here an instance is a MembershipInline formset NOT a group...
            instance.someunsetfield = something

            # I think you are creating new objects, so you could do it here.
            instance.save()