How Do I Filters the list by refModel('Model_user') in the Models?

I am unable to find how to filter the drown down which i got by using refmodel in my model which extends model_table

thanks in advance

For any view in toolkit you can use setController and getController. refModel fields from Model will set a proper controller for a form field. It uses type reference.

Once form in initialized, you can interact with controller of a field by

$field->getField('myfield')->getController()->addCondition('type','admin');

Alternatively the following might work too:

$field->getField('myfield')->dictionary()->addCondition('type','admin');