链接未调用角度指令

Question

以下指令不会产生任何异常＆amp;它确实被调用，但链接永远不会执行。你能指出我正确的方向吗？

(function() {
  var noduplicateModule,
    __hasProp = {}.hasOwnProperty;

  noduplicateModule = angular.module('noduplicate', []);

  noduplicateModule.directive('noduplicate', function() {
    return {
      restrict: 'A',
      scope: {
        ngModel: '=',
        bindAttr: '='
      },
      require: 'ngModel',
      link: function (scope, elem, attr, ctrl) {
        var options;
        console.log("test");
        //options = getOptions(scope);
        console.log("test");
        //ngModelCtrl.$validators.noduplicate = function (viewVal) {
        //
        //  console.log("test");
        //  return true;
        //};

        elem.on('blur', function () {
          console.log("test");
        });
        elem.on('focus', function () {
          console.log("test");
        });

      }
    };
  });



}).call(this);

更新 - HTML

<select name="test" id="test" data-role="none" class="form-control" ng-model="testfield" required noduplicate="NODUPE"/>