Question

我尝试使用knockoutjs动态创建选择输入。

我的观点看起来像这样 -

<div data-bind="with: QuestionFilter">
  <form>
    <div>
      <select data-bind="options: categories, optionsText: 'name', optionsValue: 'categoryID', value: selectedCategory">
      </select>
    </div>
    <div data-bind="foreach: details">
      <select data-bind="options: subcategories, optionsText: 'name', optionsValue: 'categoryID', value: selectedSubcategory">
      </select>
    </div>
  </form>
</div>  
<script type="text/javascript">
  ko.applyBindings({
    categories =  <?php echo json_encode($categories); ?>,        
    details = ko.observableArray([])       
  });
</script>

我的JS看起来像这样 -

function QuestionFilter(categories, details) {
  var self = this;
  self.categories = ko.observableArray(categories);
  self.subcategories = ko.observableArray([]);
  self.selectedCategory = ko.observable();
  self.selectedSubcategory = ko.observable();
  self.superSubcategories = ko.observableArray([]);

  self.selectedCategory.subscribe(function(category) {
    function search(nameKey, myArray){
      for (var i=0; i < myArray.length; i++) {
        if (myArray[i].parentCategory_id === nameKey) {
          self.subcategories.push(myArray[i]);
        }
      }
    }   
    search(category, categories);
    details.push({ firstName: self.subcategories()});
  });

  self.selectedSubcategory.subscribe(function(subcategory) {
    function subsearch(nameKey, myArray){
      for (var i=0; i < myArray.length; i++) {
        if (myArray[i].parentCategory_id === nameKey) {
          self.superSubcategories.push(myArray[i]);
    }
      }
    }
   subsearch(subcategory, categories);
   details.push({ firstName: self.superSubcategories()});
  });

因此，变量selectedCategory将按预期执行并触发self.selectedCategory.subscribe中的函数。变量selectedSubcategory将无法按预期执行，而是会抛出以下错误 - ReferenceError: selectedSubcategory is not defined。我认为这与在foreach绑定中使用with绑定有关，但我不确定。其他所有工作都按预期工作，我甚至用它来成功地将几个对象添加到details数组中。

需要任何想法或澄清吗？

Answer 1

看起来我没有在正确的上下文中访问selectedSubcategory。预先$parents[0].给出了期望的结果。所以它看起来像$parents[0].selectedSubcategory。奇怪的是，$parents应该提供与$parents[0]相同的上下文，但在这种情况下它不起作用......

knockoutjs传递值时使用foreach内部绑定抛出引用错误

1 个答案: