Angularjs 监视父作用域的变化 [英] Angularjs watch for change in parent scope

问题描述

我正在编写指令，我需要观察父作用域的变化.不确定我是否以首选方式执行此操作，但它不适用于以下代码:

I'm writing a directive and I need to watch the parent scope for a change. Not sure if I'm doing this the preferred way, but its not working with the following code:

  scope.$watch(scope.$parent.data.overlaytype,function() {
    console.log("Change Detected...");
  })

它记录了窗口加载，但不会再记录，即使overlaytype改变了.

This it logged on window load, but never again, even when overlaytype is changed.

如何查看overlaytype 的变化?

这里是整个指令.不完全确定为什么我要获得儿童范围

here is the entire Directive. Not entirely sure why I'm getting a child scope

/* Center overlays vertically directive */
aw.directive('center',function($window){
  return {
    restrict : "A",
    link : function(scope,elem,attrs){

      var resize = function() {
        var winHeight = $window.innerHeight - 90,
            overlayHeight = elem[0].offsetHeight,
            diff = (winHeight - overlayHeight) / 2;
            elem.css('top',diff+"px");
      };

      var watchForChange = function() {
        return scope.$parent.data.overlaytype;
      }
      scope.$watch(watchForChange,function() {
        $window.setTimeout(function() {
          resize();
        }, 1);
      })

      angular.element($window).bind('resize',function(e){
        console.log(scope.$parent.data.overlaytype)
        resize();
      });
    }
  };
});

推荐答案

您应该在子作用域上拥有 data 属性，作用域在父作用域和子作用域之间使用原型继承.

You should have the data property on your child scope, scopes use prototypal inheritance between parent and child scopes.

此外，$watch 方法期望的第一个参数是要计算的表达式或函数，而不是来自变量的值.因此，您应该改为发送它.

Also, the first argument the $watch method expects is an expression or a function to evaluate and not a value from a variable., So you should send that instead.

这篇关于Angularjs 监视父作用域的变化的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！