Generating variable for ng-class dynamically using Expression in AngularJs
You're almost there, it's myBoxes[boxName]
and not myBoxes.{{boxName}}
.
Something like this:
<!doctype html>
<html ng-app="myApp">
<head>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script src="http://code.angularjs.org/1.1.2/angular.min.js"></script>
<script type="text/javascript">
var myApp = angular.module('myApp', []);
myApp.controller('MainCtrl', ['$scope', function($scope){
$scope.boxNameList=['Box1','Box2','Box3'];
$scope.myBoxes={
Box1: "redBackground",
Box2: "blackBackground",
Box3: "blackBackground"
}
}]);
</script>
<style type="text/css">
.redBackground{
background-color: red;
}
.blackBackground{
background-color: black;
}
</style>
</head>
<body ng-controller="MainCtrl">
<div ng-repeat="name in boxNameList">
<div ng-class="myBoxes[name]">Box1</div>
</div>
</body>
</html>
Durin
Updated on July 09, 2022Comments
-
Durin almost 2 years
Here is snippet from my HTML code.
<div ng-repeat="boxName in boxNameList"> <div ng-class="myBoxes.{{boxName}}">{{boxName}}</div> </div>
What I am trying to do: I have created 3 div elements which will be at the top of a screen using the above written snippet. Each div element will be given a shape of a box using css. A box(div) can have either red color as its background or black color as its background.
CSS for the two colors is:
.redBackground{ background-color: red; } .blackBackground{ background-color: black; }
Here is a snippet from my controller:
$scope.boxNameList=['Box1','Box2','Box3']; $scope.myBoxes={ Box1: "redBackground", Box2: "blackBackground", Box3: "blackBackground" }
In this example I have made
$scope.myBoxes
as a static Json but at runtime I plan to generate Json code so that I can dynamically assign background colors to my boxes.Problem that I am facing: Well the problem is that I am not able to see the boxes with colors at all. The ng-class variable name in this case as you can see is also generated dynamically. If I do not use ng-repeat and do not dynamically generate ng-class variable name then it works fine. For e.g for the snippet given below when I dynamically change the value of the varibales
myBoxes.Box1
myBoxes.Box2
andmyBoxes.Box3
then it works perfectly.<div ng-class="myBoxes.Box1">Box1</div> <div ng-class="myBoxes.Box2">Box2</div> <div ng-class="myBoxes.Box3">Box3</div>
However if I generate the ng-class variable dynamically
"myBoxes.{{boxName}}"
then it doesn't behave like a variable. I am sure there would be a better way to achieve what I am trying to do however I was not able to find that after hours and hours of googling/trial and error. Would be glad if someone could help me. -
Durin over 11 yearsAwesome! works like a charm. But I still wonder why it worked by accessing the Json object values using array notation instead of the normal way of accessing Json objects using dot notation. I am a javscript newbie, I apologize if I am asking a very fundamental question.
-
Anders Ekdahl over 11 yearsFirst off,
myBoxes.{{boxName}}
isn't a valid expression in Angular, butmyBoxes.boxName
andmyBoxes[boxName]
are. In Javascript, these expressions are the same:myBoxes.boxName
,myBoxes['boxName']
andvar name = 'boxName'; myBoxes[name];
which means that when you want a property on an object but you don't know what the property name is, you can use array notation with a variable instead. -
Durin over 11 yearsEdit: oh! then in that case
{{'myBoxes.' + name}}
should also work for me since it is a valid angular js expression. But it doesn't work for me. Thanks for the explanation. -
Anders Ekdahl over 11 yearsYes, you could, but if you use {{expr}} in ng-class, the expression won't be re-evaluated later. See the difference here: jsfiddle.net/DwpXs
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Karma about 9 yearsCan't seem to get it working. I have an array of objects, like: {name: 'christina', gender: 'female'}. I tried doing ng-repeat="person in people" and inside ng-class="person['gender']" but can't get the .female class attached.