angularjs 警报消息未正确出现答案

【问题标题】：angularjs alert message not coming properlyangularjs 警报消息未正确出现
【发布时间】：2018-06-03 03:10:12
【问题描述】：

当没有选择下拉菜单时，消息来了，但是当任何一个或多个下拉菜单被选中时，消息也来了请选择至少一个。下面是我的 angularjs

$scope.check = function () {


 if ($scope.landing.class == null || $scope.landing.class == undefined|| $scope.landing.class == "" && $scope.landing.fueltype == undefined || $scope.landing.fueltype == null || $scope.landing.fueltype == "" && $scope.landing.transmiss == null || $scope.landing.transmiss == undefined || $scope.transmiss == "" && $scope.landing.driving == null || $scope.landing.driving == undefined || $scope.driving == "" && $scope.landing.pick == null || $scope.landing.pick == undefined || $scope.landing.pick == "" && $scope.landing.stat == null || $scope.landing.stat == undefined || $scope.landing.stat == "") {
            alert('Please select atleast one')
        }
    }

【问题讨论】：

来不及？
在选择至少一个下拉菜单后，它不应该出现消息！！！

标签： angularjs model-view-controller asp.net-mvc-5 angularjs-scope

【解决方案1】：

你可能需要额外的括号...

if (($scope.landing.class == null || $scope.landing.class == undefined || $scope.landing.class == "" )
&& (
$scope.landing.fueltype == undefined || $scope.landing.fueltype == null || $scope.landing.fueltype == "" )
&& (....

但总的来说，这很难看，您必须找到更好/更智能的方法来进行此验证..

【讨论】：