Django admin return custom error message during model saving

I would like to return some custom error messages in save_model function of Django admin page.

class EmployerAdmin(admin.ModelAdmin):
  exclude = ('update_user','updatedate','activatedate','activate_user')

  def save_model(self, request, obj, form, change):
    if obj.department != None and obj.isDepartmentSuggested:
        obj.isDepartmentSuggested =False
    else:
       return "You don't set a valid department. Do you want to 开发者_StackOverflow中文版continue ?"

    obj.update_user = request.user
    obj.updatedate = datetime.datetime.now()
    obj.save()

Of course, Else part isn't correct but I want to illustrate what I want.

I am glad to suggest me a way or document to do that. Thanks

You need to use a form to do your validation in your EmployerAdmin:

#forms.py
from your_app.models import Employer

class EmployerAdminForm(forms.ModelForm):
    class Meta:
        model = Employer

    def clean(self):
        cleaned_data = self.cleaned_data
        department = cleaned_data.get('department')
        isDepartmentSuggested = cleaned_data.get('isDepartmentSuggested')
        if department == None and not isDepartmentSuggested:
            raise forms.ValidationError(u"You haven't set a valid department. Do you want to continue?")
        return cleaned_data

#admin.py
from django.contrib import admin
from your_app.forms import EmployerAdminForm
from your_app.models import Employer

class EmployerAdmin(admin.ModelAdmin):
    exclude = ('update_user','updatedate','activatedate','activate_user')
    form = EmployerAdminForm

admin.site.register(Employer, EmployerAdmin)

Hope that helps you out.

I'm using Django 1.6.3, and I'd like to add to Brandon's answer.

Add admin.site.register(Employer, EmployerAdmin) as a separate line below the EmployerAdmin class; that is, below form = EmployerAdminForm, unindented.

It took me some time to figure out why Brandon's answer wasn't working for me and the validations weren't running, apparently, you just need to register it on admin first.

Cheers.