如果变量为空，如何显示/隐藏 [英] How to show/hide if variable is null

问题描述

我想根据变量是否为空来显示/隐藏 div.

I'm wanting to show/hide a div based on whether a variable is null or not.

<div ng-show="myvar"></div>

注意:在我的例子中变量是一个对象.

Note: the variable in my case is an object.

一个非常简单的问题，但我似乎无法解决.

A very simple question, but I can't seem to make it work.

谢谢.

推荐答案

澄清一下，上面的例子确实有效，我在例子中的代码由于无关的原因而无效.

To clarify, the above example does work, my code in the example did not work for unrelated reasons.

如果 myvar 为 false、null 或以前从未使用过(即从未调用过 $scope.myvar 或 $rootScope.myvar)，则 div 将不会显示.一旦为其分配了任何值，div 就会显示，除非该值特别为 false.

If myvar is false, null or has never been used before (i.e. $scope.myvar or $rootScope.myvar never called), the div will not show. Once any value has been assigned to it, the div will show, except if the value is specifically false.

以下将导致 div 显示:

$scope.myvar = "Hello World";

或

$scope.myvar = true;

以下将隐藏 div:

$scope.myvar = null;

或

$scope.myvar = false;

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