Using ng-options in Angular to make four distinct selections: a guide

Question

Using ng-options in Angular to make four distinct selections: a guide

JS:

angular
.module('app', [])

function MainCtrl() {
    var ctrl = this;

    ctrl.selectionList = [
        { id: 1, name: 'apple'},
        { id: 2, name: 'banana'},
        { id: 3, name: 'grapes'},
        { id: 4, name: 'carrot'}
    ];

    ctrl.selectedThing = ctrl.selectionList[0].name; 

}

angular
.module('app', [])
.controller('MainCtrl', MainCtrl);

HTML:

<div class="row">

    <div class="col-sm-3 col-xs-12 unit">
        <select 
        ng-model="ctrl.selectedThing"
        ng-options="selections.name as selections.name for selections in ctrl.selectionList">
        </select>
    </div>

</div><!--end of first row-->

When implementing this code, it results in creating four different selections. The issue arises when selecting an option like "apple" on one selection, causing all other selections to also display "apple." Is there a way to address this using ng-options or should I resort to coding the select element directly in HTML?

javascript angularjs

Answer 1

Answer №1

To solve your issue, it is important to utilize ng-options instead of focusing on any other problems. The reason you are encountering difficulties is likely due to having the same ng-model for all select elements linked to the ctrl variable. This means that modifying one dropdown will affect a single variable that pertains to all four dropdowns. In order to address this, you should either create an array for your selected items or have four distinct instances of a selected variable.

ctrl.selectedThings = [ctrl.selectedList[0].name, '', '', ''];

In your view, implement the following approach...

<select 
        ng-model="ctrl.selectedThings[rowIndex]"
        ng-options="selections.name as selections.name for selections in ctrl.selectionList">
        </select>

This solution may not be optimal for scenarios with more than 4 items, but it can be adjusted to accommodate dynamic requirements.

Answer 2

To solve your issue, it is important to utilize ng-options instead of focusing on any other problems. The reason you are encountering difficulties is likely due to having the same ng-model for all select elements linked to the ctrl variable. This means that modifying one dropdown will affect a single variable that pertains to all four dropdowns. In order to address this, you should either create an array for your selected items or have four distinct instances of a selected variable.

ctrl.selectedThings = [ctrl.selectedList[0].name, '', '', ''];

In your view, implement the following approach...

<select 
        ng-model="ctrl.selectedThings[rowIndex]"
        ng-options="selections.name as selections.name for selections in ctrl.selectionList">
        </select>

This solution may not be optimal for scenarios with more than 4 items, but it can be adjusted to accommodate dynamic requirements.

Answer 3

Answer №2

It seems like your code is functioning properly, can you please double-check and confirm?

(function ()
{
    var app = angular.module("app", []);

    function HomeController()
    {
        var vm = this;
        vm.selectionList = [
            { id: 1, name: 'apple'},
            { id: 2, name: 'banana'},
            { id: 3, name: 'grapes'},
            { id: 4, name: 'carrot'}
        ];

    }

    app.controller("HomeController", [HomeController]);

})();

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<!DOCTYPE html>
<html lang="en" ng-app="app">
    <head>
        <meta charset="UTF-8">
        <title>Angular JS App</title>        
    </head>
    <body>

        <div class="container" ng-controller="HomeController as homeCtrl">

            <div class="row">

                <div class="col-sm-3 col-xs-12 unit">
                    <select
                            ng-model="homeCtrl.selectedThing"
                            ng-options="selections.name as selections.name for selections in homeCtrl.selectionList">
                    </select>
                    <pre>{{homeCtrl.selectedThing}}</pre>
                </div>

            </div><!--end of first row-->
           
        </div>


    </body>
</html>

Answer 4

It seems like your code is functioning properly, can you please double-check and confirm?

(function ()
{
    var app = angular.module("app", []);

    function HomeController()
    {
        var vm = this;
        vm.selectionList = [
            { id: 1, name: 'apple'},
            { id: 2, name: 'banana'},
            { id: 3, name: 'grapes'},
            { id: 4, name: 'carrot'}
        ];

    }

    app.controller("HomeController", [HomeController]);

})();

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<!DOCTYPE html>
<html lang="en" ng-app="app">
    <head>
        <meta charset="UTF-8">
        <title>Angular JS App</title>        
    </head>
    <body>

        <div class="container" ng-controller="HomeController as homeCtrl">

            <div class="row">

                <div class="col-sm-3 col-xs-12 unit">
                    <select
                            ng-model="homeCtrl.selectedThing"
                            ng-options="selections.name as selections.name for selections in homeCtrl.selectionList">
                    </select>
                    <pre>{{homeCtrl.selectedThing}}</pre>
                </div>

            </div><!--end of first row-->
           
        </div>


    </body>
</html>

Answer 5

Answer №3

When you use ng-model="ctrl.selectedThing" for each <select> tag, they will all synchronize to the same value because they are connected to the same scope property. It's like having multiple variables pointing to the same information: if one is modified, accessing any of them will yield the same outcome.

To address this issue, you should link each select to a distinct property in the scope, such as ctrl.selectedThing1,2,...n. While this approach may not be very scalable, it will resolve the problem at hand.

Answer 6

When you use ng-model="ctrl.selectedThing" for each <select> tag, they will all synchronize to the same value because they are connected to the same scope property. It's like having multiple variables pointing to the same information: if one is modified, accessing any of them will yield the same outcome.

To address this issue, you should link each select to a distinct property in the scope, such as ctrl.selectedThing1,2,...n. While this approach may not be very scalable, it will resolve the problem at hand.

Using ng-options in Angular to make four distinct selections: a guide

Answer №1

Answer №2

Answer №3

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