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pythondjangosignalsdjango-signalsm2m

Signal m2m_changed never triggered

class Lab(Model):
  pass

class School(Model):
  labs = ManyToManyField(Lab, related_name='schools')

def m2m_changed_labs(*args, **kwargs):
  pass

m2m_changed.connect(m2m_changed_labs, sender=Lab.schools)

The m2m_changed signal is never triggered, therefore the m2m_changed_labs function is never called. I want the m2m_changed_labs function to be called each time a school is added to or removed from a lab.

Solution

  • Have you tried sender=School.labs.through?

    and with your receiver method like this:

    def m2m_changed_labs(sender, **kwargs):  # notice sender instead of *args
    print "signal received"

    That's the sender used in the example from the docs.