angularjs NG选项自定义过滤器不工作 [英] angularjs ng-options with custom filter not working

问题描述

不好意思再问这个问题，但没有答案或解决方法已被确定。

Sorry to ask this question again but no answer or workaround has been identified.

这是这个问题的后续：<一href=\"http://stackoverflow.com/questions/24414417/angularjs-select-with-filter-leaves-first-line-empty-but-not-when-filter-is-appl\">Stackoverflow

我描述这一问题的plunker（基本上把一个树形结构中的一个下拉列表）：

I have a plunker which describes the issue (basically putting a tree structure in a dropdown list) :

Plunker例如

如图所示，第一选择不选择的价值，并得到回一个空行 - 这也是一个谜

As illustrated the first select does not select the value and gets back to an empty line - which is also a mystery.

我一直没能找到任何类似的情况，我很接近放弃，所以这是最后的机会了。

I have not been able to find any similar cases and I am close to giving up so this is the last chance.

重点code区是过滤器和initTreeSelect功能：

Key code areas are the filter and the initTreeSelect function :

$scope.initTreeSelect = function(tree){
   $scope.filteredFields = $filter('flattenTree')(tree);
   return $scope.filteredFields[0];

};


angular.module('myApp.filters', []).filter('flattenTree', function (OrgSvc) {
return function (array) {
  var arrayToReturn = [];        
    arrayToReturn = OrgSvc.flattenTree(array);
    return arrayToReturn;

};})

您的帮助将非常AP preciated！
谢谢

Your help would be very much appreciated! Thanks

推荐答案

什么大雁莫雷诺Leon在他的回答中写道实际上是正确的。而真正的问题是，角度保持丢失模型数据的轨迹（因为/阵列由引用标识默认的对象）。

What Dayan Moreno Leon wrote in his answer is actually correct. And the problem really is that angular keeps losing track of the model data (because by default objects/arrays are identified by reference).

这是挫败，因为你的 flattenTree 保持返回新创建的对象：

This is thwarted, because your flattenTree keeps returning newly created objects:

flatTree.push({id:tree[i].id, display:tree[i].display, parentId:tree[i].parentId});

有关虽然你的具体问题，我认为使用轨道由将有所帮助，例如：

For your concrete problem though, I think using track by will help, e.g.:

<select
  class='form-control' 

  ng-model="treeValue1"
  ng-init="treeValue1 = initTreeSelect(fields)"
  ng-options="element as element.display for element in fields | flattenTree track by element.id"
></select>  

演示： http://plnkr.co/edit/J8PyypC61uzx8PPNV6Zu?p=preVIEW

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