angularjs - How do I access the child ngModel from a directive? -

like in this question, want add .error on form field's parent .control-group when scope.$invalid true.

however, hardcoding form name in ng-class="{ error: formname.fieldmodel.$invalid }" means can't reuse in different forms, plus i'd rather not repeat declaration everywhere.

i figured directive looks work:

<div class="control-group" error-on="model1, model2">   <input ng-model="model1">   <input ng-model="model2"> </div> 

so when either model1 or model2 not valid, .control-group gets .error added.

my attempt here. possible access models directive, given model names?

if there's better approach, i'd love hear too.

i don't think writing custom directive necessery use-case ng-form directive created situations those. directive's documentation:

it useful nest forms, example if validity of sub-group of controls needs determined.

taking code example 1 write:

<div class="control-group" ng-class="{ error: mycontrolgroup1.$invalid }>   <ng-form name="mycontrolgroup1">     <input ng-model="model1">     <input ng-model="model2">   </ng-form> </div> 

by using technique don't need repeat expressions used in ng-model , can reuse fragment inside form.