Using JSON Object for Default Selection in an Angular Dropdown Menu

Question

Using JSON Object for Default Selection in an Angular Dropdown Menu

Here is some code I have that fills in a specific select item on a webpage:

<select ng-model="activity.selectedParent" ng-options="parent as parent.title for parent in parents track by parent._id"></select><br>

I'm curious if there's a way to set a default option where I can give it a Title and an ID. For example, if the default is selected, then

activity.selectedParent.Title = "None"

and activity.selectedParent.id = 0. Can this be specified within the <select> tag using Angular directives? If not, what is the most effective approach to achieve this?

javascript angularjs json

Answer 1

Answer №1

If you are looking to set an object as selected even if the default option is chosen, there are two ways to achieve this:

Utilize the ngInit directive within your select tag like this:
```
ng-init="selectedParent = { '_id': 0, 'title': 'None' };"
```

You can also initialize your object in the controller:

$scope.selectedParent = { "_id": 0, "title": "None" };

EDIT:

If you want a default option instead of leaving it blank at the start, you can simply add this element to your existing array by using the unshift method to place it as the first element:

$scope.parents.unshift($scope.selectedParent);

A code snippet demonstrating this:

var app = angular.module('app', []);

app.controller('mainCtrl', function($scope) {
  $scope.parents = [  
     {  
        "_id":1,
        "title":"first"
     },
     {  
        "_id":2,
        "title":"second"
     },
     {  
        "_id":3,
        "title":"third"
     },
     {  
        "_id":4,
        "title":"four"
     }
  ];

  $scope.selectedParent = {
    "_id": 0,
    "title": "None"
  };

  $scope.parents.unshift($scope.selectedParent);
});

<!DOCTYPE html>
<html ng-app="app">

<head>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.7/angular.min.js"></script>
</head>

<body ng-controller="mainCtrl">
  <select ng-model="selectedParent" ng-options="parent as parent.title for parent in parents track by parent._id"></select>
  <hr> 
  Selected: <span ng-bind="selectedParent | json"></span>
</body>

</html>

Answer 2

If you are looking to set an object as selected even if the default option is chosen, there are two ways to achieve this:

Utilize the ngInit directive within your select tag like this:
```
ng-init="selectedParent = { '_id': 0, 'title': 'None' };"
```

You can also initialize your object in the controller:

$scope.selectedParent = { "_id": 0, "title": "None" };

EDIT:

If you want a default option instead of leaving it blank at the start, you can simply add this element to your existing array by using the unshift method to place it as the first element:

$scope.parents.unshift($scope.selectedParent);

A code snippet demonstrating this:

var app = angular.module('app', []);

app.controller('mainCtrl', function($scope) {
  $scope.parents = [  
     {  
        "_id":1,
        "title":"first"
     },
     {  
        "_id":2,
        "title":"second"
     },
     {  
        "_id":3,
        "title":"third"
     },
     {  
        "_id":4,
        "title":"four"
     }
  ];

  $scope.selectedParent = {
    "_id": 0,
    "title": "None"
  };

  $scope.parents.unshift($scope.selectedParent);
});

<!DOCTYPE html>
<html ng-app="app">

<head>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.7/angular.min.js"></script>
</head>

<body ng-controller="mainCtrl">
  <select ng-model="selectedParent" ng-options="parent as parent.title for parent in parents track by parent._id"></select>
  <hr> 
  Selected: <span ng-bind="selectedParent | json"></span>
</body>

</html>

Answer 3

Answer №2

To ensure that the default value you want to set is included in the array used for ng-options, simply add it to the array.

Start by defining the selectedParent variable in the controller

$scope.selectedParent = { "_id": 0, "title": "None" };

Next, insert it at the beginning of the array

$scope.parents.splice(0,0,$scope.selectedParent);

Lastly, assign the ng-model of the select element to ng-model="$scope.selectedParent"

Answer 4

To ensure that the default value you want to set is included in the array used for ng-options, simply add it to the array.

Start by defining the selectedParent variable in the controller

$scope.selectedParent = { "_id": 0, "title": "None" };

Next, insert it at the beginning of the array

$scope.parents.splice(0,0,$scope.selectedParent);

Lastly, assign the ng-model of the select element to ng-model="$scope.selectedParent"

Using JSON Object for Default Selection in an Angular Dropdown Menu

Answer №1

Answer №2

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