Angularjs 用角表示错误

为什么这个代码会给出错误？我收到错误“无法设置未定义的属性'show'”

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stun
分解
从历史记录中删除

函数deathraymenumcontroller（$scope）{
$scope.menuState.show=false；
$scope.toggleMenu=函数（）{
$scope.menuState.show=！$scope.menuState.show；
};
//死亡射线的功能留给读者作为练习
}

您将为

$scope.menuState

对象分配

show

属性，但您没有

$scope.menuState

对象

因此，您需要做的是，创建一个

$scope.menuState

对象作为控制器的开头

function DeathrayMenuController($scope) {
   $scope.menuState = {};           // initialize the object first.
   $scope.menuState.show = false;
   $scope.toggleMenu = function() {
       $scope.menuState.show = !$scope.menuState.show;
   };
   // death ray functions left as exercise to reader
}

---

如果

$scope.menustate

未定义，则无法在

$scope.menustate

上设置

show

属性。您需要首先对其进行初始化：

$scope.menuState = {};
$scope.menuState.show = false;

或者：

$scope.menuState = {
    show: false
};

---

您没有首先定义$scope.menuStage。请尝试以下方法：

<div ng-controller='DeathrayMenuController'>
<button ng-click='toggleMenu()'>Toggle Menu</button>
<ul ng-show='menuState_show'>
<li ng-click='stun()'>Stun</li>
<li ng-click='disintegrate()'>Disintegrate</li>
<li ng-click='erase()'>Erase from history</li>
</ul>
<div/>

function DeathrayMenuController($scope) {
$scope.menuState_show = false;
$scope.toggleMenu = function() {
$scope.menuState_show = !$scope.menuState_show;
};
// death ray functions left as exercise to reader
}

切换菜单

stun
分解
从历史记录中删除

函数deathraymenumcontroller（$scope）{
$scope.menuState\u show=false；
$scope.toggleMenu=函数（）{
$scope.menuState\u show=！$scope.menuState\u show；
};
//死亡射线的功能留给读者作为练习
}

<div ng-controller='DeathrayMenuController'>
<button ng-click='toggleMenu()'>Toggle Menu</button>
<ul ng-show='menuState_show'>
<li ng-click='stun()'>Stun</li>
<li ng-click='disintegrate()'>Disintegrate</li>
<li ng-click='erase()'>Erase from history</li>
</ul>
<div/>

function DeathrayMenuController($scope) {
$scope.menuState_show = false;
$scope.toggleMenu = function() {
$scope.menuState_show = !$scope.menuState_show;
};
// death ray functions left as exercise to reader
}