如何正确控制Angular指令的$dirty和$pure状态

我正在尝试创建一个角度指令，该指令将组成一个KendoUI TreeView控件和一个文本输入，以便它搜索输入的文本并选择项目。我有这个功能，但我希望指令在表单中表现良好，这样当复选框值更改时，就会设置表单的脏属性。

不幸的是，现在的行为是，当有人在输入中输入文本时，from会被设置为dirty（这不是所需的行为），并且选中复选框没有效果。

我希望在表单上调用$setDirty（），但它对我的函数不可见，我希望有一种干净的方法可以使它可见，而不是将它添加到$scope中，这也不能解决$dirty设置为true但输入搜索文本的问题。

我创建了一个Plunk来演示这个问题。

这是指令的代码：

var serviceRoot = "http://demos.telerik.com/kendo-ui/service";
 angular.module("KendoDemos", ["kendo.directives"])
   .controller("MyCtrl", function($scope, $http) {
     $scope.treeData = new kendo.data.HierarchicalDataSource({
       data: [{
         text: "Cat"
       }, {
         text: "Dog",
         items: [{
           text: "Fido"
         }, {
           text: "Rover"
         }]
       }, {
         text: "Rabbit",
         checked: true
       }]
     });
   });
 (function() {
   'use strict';
   var app = angular.module('KendoDemos');
   var template = '<div>	<div class="input-group">		<input type="text" ng-click="textNotFound=false"			   class="form-control" placeholder="Find node"			   ng-model="searchText" ng-enter="search()" ng-esc="searchText='''';textNotFound = false;">		<div class="input-group-btn">			<span class="btn btn-default" ng-click="search()"><span class="fa fa-search clickable"				style="font-size: 14px; height: 18px"></span></span>		</div>	</div>	<div id="treeview" kendo-tree-view="searchTree" k-data-source="dataSource" k-load-on-demand="false" k-on-check="onCheck(kendoEvent)"	      k-options="{checkboxes:true }">		<span k-template>{{dataItem.text}}</span>	</div></div>'
   app.directive('searchableTree', function() {
     //Usage:
     //<div data-searchable-tree ng-model="vm.treeData"></div>
     var directive = {
       template: template,
       require: '?^form',
       replace: true,
       transclude: true,
       scope: {
         'dataSource': '=ngModel',
         'controlId': '@id'
       },
       restrict: 'AE',
       link: function($scope, element, attrs, formCtrl) {
         $scope.search = function(id) {
           var tree = $scope.searchTree;
           var node = tree.findByText($scope.searchText);
           tree.expandTo($scope.searchTree.dataItem(node));
           tree.select(node);
           tree.dataItem(node).set("checked", true);
           //var checkbox = $(node).find(":checkbox");
           //checkbox.prop("checked", true);
         }
         $scope.setSelected = function(id) {
           alert(id);
         }
         $scope.onSelect = function(id) {
           alert(id);
         }
         $scope.onCheck = function(e) {
           var checkbox = $(e.node).find(":checkbox");
           var checked = checkbox.prop("checked");
           //updateValidity(e.node, checked);
         }
       }
     };
     return directive;
   });
   app.directive('ngEnter', function() {
     return function(scope, element, attrs) {
       element.bind("keydown keypress", function(event) {
         if (event.which === 13) {
           scope.$apply(function() {
             scope.$eval(attrs.ngEnter);
           });
           event.preventDefault();
         }
       });
     };
   });
   app.directive('ngEsc', function() {
     return function(scope, element, attrs) {
       element.bind("keydown keypress", function(event) {
         if (event.which === 27) {
           scope.$apply(function() {
             scope.$eval(attrs.ngEsc);
           });
           event.preventDefault();
         }
       });
     };
   });
 })();

/* Styles go here */
html {
  font-size: 12px;
  font-family: Arial, Helvetica, sans-serif;
}
#example {
  text-align: center;
}
.demo-section {
  display: inline-block;
  vertical-align: top;
  width: 320px;
  height: 300px;
  text-align: left;
  margin: 0 2em;
}
.clickable {
  cursor: pointer;
}

<link rel="stylesheet" href="http://cdn.kendostatic.com/2014.3.1411/styles/kendo.common.min.css" />
<link rel="stylesheet" href="http://cdn.kendostatic.com/2014.3.1411/styles/kendo.default.min.css" />
<link rel="stylesheet" href="http://cdn.kendostatic.com/2014.3.1411/styles/kendo.dataviz.min.css" />
<link rel="stylesheet" href="http://cdn.kendostatic.com/2014.3.1411/styles/kendo.dataviz.default.min.css" />
<link rel="stylesheet" href="http://cdn.kendostatic.com/2014.3.1411/styles/kendo.default.mobile.min.css" />
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">
<script src="http://cdn.kendostatic.com/2014.3.1411/js/jquery.min.js"></script>
<script src="http://cdn.kendostatic.com/2014.3.1411/js/angular.min.js"></script>
<script src="http://cdn.kendostatic.com/2014.3.1411/js/kendo.all.min.js"></script>
<body>
  <div id="example" ng-app="KendoDemos" ng-controller="MyCtrl">
    <form name='myForm'>
      <div name='myTree' data-searchable-tree ng-model="treeData"></div>
    </form>
    <hr/>
    <div>Directive is {{myForm.myTree.$dirty ? 'dirty' : 'pristine'}}</div>
    <hr/>
    <div>Form is {{myForm.$dirty ? 'dirty' : 'pristine'}}</div>
  </div>
</body>