Updating ngModel value dynamically from controller

Question

Updating ngModel value dynamically from controller

I have been trying to update the value of an ngModel variable from my controller, but it doesn't seem to be reflecting in the views. Despite looking at other solutions on SO, nothing has worked for me so far. I am looking for a solution that doesn't involve creating a new directive and have also attempted wrapping the change in $scope.$apply without any luck.

You can see the issue demonstrated in this plunkr.

Below is the code snippet from the plunkr:

JavaScript Controller:

    app.controller('MainCtrl', function($scope) {
  $scope.Attachment = "something"
  $scope.change = function () {
      $scope.$apply(function() {
          $scope.Attachment = "otherthing";
      });
}

HTML:

<body ng-controller="MainCtrl">
    <section class="content" ng-app="offer">
        <div>
            <button name="change" ng-click="change()" ng-model="Attachment">change</button>
            <!-- <input name="Attachment" type="file" class="file_up" onchange="angular.element(this).scope().change(this)" ng-model="Attachment" /> -->
            <span>{{Attachment}}</span>

        </div>
    </section>
</body>

javascript angularjs angular-ngmodel angularjs-ng-model

Answer 1

Answer №1

It is recommended to bind to object properties rather than primitive types.
In this case, you are binding to a string which is a primitive type and cannot be changed.
The use of $apply is not necessary as Angular will automatically handle it for you.

If you store your data as a property of an object, you won't lose the reference:

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

app.controller('Ctrl', function($scope) {
  //Updated here:
  $scope.data = {
    Info: "sample"
  }

  $scope.update = function() {
    //Removed $apply from here
    $scope.data.Info = "updated";
  }
});

To reflect this change in the HTML, simply update:

<span>{{data.Info}}</span>

UPDATE: While other responses may be accurate, I wanted to highlight the best practice for binding. Check out the updated demo here.

Answer 2

It is recommended to bind to object properties rather than primitive types.
In this case, you are binding to a string which is a primitive type and cannot be changed.
The use of $apply is not necessary as Angular will automatically handle it for you.

If you store your data as a property of an object, you won't lose the reference:

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

app.controller('Ctrl', function($scope) {
  //Updated here:
  $scope.data = {
    Info: "sample"
  }

  $scope.update = function() {
    //Removed $apply from here
    $scope.data.Info = "updated";
  }
});

To reflect this change in the HTML, simply update:

<span>{{data.Info}}</span>

UPDATE: While other responses may be accurate, I wanted to highlight the best practice for binding. Check out the updated demo here.

Answer 3

Answer №2

To enhance the functionality of your code, eliminate the ng-model attribute from the button element and get rid of the $scope.$apply function from the change handler:

http://example.com/sample-code

Answer 4

To enhance the functionality of your code, eliminate the ng-model attribute from the button element and get rid of the $scope.$apply function from the change handler:

http://example.com/sample-code

Answer 5

Answer №3

Feel free to try out this solution

function NewController($scope) {

  $scope.File = "example"
  $scope.modify = function() {

    $scope.File = "different";

  }
}

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.22/angular.min.js"></script>

<div ng-app ng-controller="NewController">
  <button name="modify" ng-click="modify()" ng-model="File">modify</button>

  <span>{{File}}</span>
</div>

Answer 6

Feel free to try out this solution

function NewController($scope) {

  $scope.File = "example"
  $scope.modify = function() {

    $scope.File = "different";

  }
}

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.22/angular.min.js"></script>

<div ng-app ng-controller="NewController">
  <button name="modify" ng-click="modify()" ng-model="File">modify</button>

  <span>{{File}}</span>
</div>

Answer 7

Answer №4

Avoid using $scope.$apply() if possible. I updated the plunkr to automatically update the view without it.

app.controller('MainCtrl', function($scope) {
  $scope.File = "example"
  $scope.update = function () {
      $scope.File = "another";
  }
});

Answer 8

Avoid using $scope.$apply() if possible. I updated the plunkr to automatically update the view without it.

app.controller('MainCtrl', function($scope) {
  $scope.File = "example"
  $scope.update = function () {
      $scope.File = "another";
  }
});

Updating ngModel value dynamically from controller

Answer №1

Answer №2

Answer №3

Answer №4

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