Yii2: how to use custom validation function for activeform?

Question

In my form\'s model, I have a custom validation function for a field defined in this way

class SignupForm extends Model
{
    public function rules()
    {
          


        

Answer 1

Your syntax on rules should be something like this man,

[['birth_date'], 'checkDateFormat']

not this

['birth_date', 'checkDateFormat']

So in your case, it should look like below

...
class SignupForm extends Model
{
    public function rules()
    {
        // Notice the different with your previous code here
        return [
            [['birth_date'], 'checkDateFormat'], 

            // other rules
        ];
    }

    public function checkDateFormat($attribute, $params)
    {
        // no real check at the moment to be sure that the error is triggered
        $this->addError($attribute, Yii::t('user', 'You entered an invalid date format.'));
    }
}