How to call QValidator derived object

[bruccutler]

I have a QLineEdit field which I need to have the user either enter 0 characters or 10 characters and nothing in between. I have written a QValidator class that returns invalid if anything other than 0 or 10 characters are entered. It also returns intermediate other times.

How do I prevent the user from moving out of the QLineEdit field until the field is correct?

Here's my code snippets:
(validate routine from QValidator derived class)

QValidator::State ValidatorWepKey::validate(QString &input, int &pos) const 
{
  if (input.length() == 0)
  {
    return Acceptable;
  }
  else if (input.length() < m_minLength)
  {
    return Intermediate;
  }
  else if (input.length() == m_minLength)
  {
    return Acceptable;
  }
  else
  {
    return Invalid;
  }
}

QValidator::State ValidatorWepKey::validate(QString &input, int &pos) const 
{
  if (input.length() == 0)
  {
    return Acceptable;
  }
  else if (input.length() < m_minLength)
  {
    return Intermediate;
  }
  else if (input.length() == m_minLength)
  {
    return Acceptable;
  }
  else
  {
    return Invalid;
  }
}

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Main code:

QLineEdit m_pKey1 = new QLineEdit();
m_pKey1->setValidator(new ValidatorWepKey(10, this)); // should prevent

QLineEdit m_pKey1 = new QLineEdit();
m_pKey1->setValidator(new ValidatorWepKey(10, this)); // should prevent

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When do I call the ValidatorWepKey.validate()? Is that when I get the signal that the user is attempting to exit the field? How do I keep them in the field until it is correct?

- BRC