AngularJS: Enabling unidirectional binding for select option to model

Utilizing a dropdown to display client names. Users have the ability to choose an existing client, which will then update the scope property:

Controller

Setting up the initial selection.

if($scope.clients.length > 0) $scope.existingClient = $scope.clients[0];

View

<select
    id='nm-existing-client-name'
    class='form-control  input-lg'
    ng-model='existingClient'
    ng-options="client.name for client in clients">
</select>

The existingClient scope property remains unchanged when the selection in the dropdown changes. Without initialization (removing the line from the controller above), the existingClient value will remain undefined.

Adding an ng-change will trigger an event when a new value is selected, but the model itself will not reflect the updated value.

This project uses AngularJS v1.2.0-rc.3.

javascriptangularjsangularjs-scope

Answer №1

It seems like you may be unintentionally working with a child scope without realizing it. Elements like ng-if, ng-repeat, ng-switch, and ng-include all generate child scopes. When you modify a value in a child scope, it creates a new value specific to that scope while the parent scope's inherited value remains unchanged. Consider using an object to store your values instead. By assigning properties to an object rather than directly on the scope, the changes will reflect on the parent scope's inherited object.

$scope.data = {
    existingClient: $scope.clients.length > 0 ? $scope.clients[0] : undefined
};

View:

<select ng-model="data.existingClient" 
        ng-options="client.name for client in clients">
</select>

You can utilize the AngularJS Batarang extension on Chrome to aid in debugging your scopes effectively.

Answer №2

Here is another method to include parameters in your $scope object:

controller:

$scope.scope = $scope;
$scope.clients = [];
$scope.existingClient = $scope.clients.length > 0 ? $scope.clients[0] : undefined;

view:

<select ng-model="scope.existingClient" ng-options="client.name for client in clients"></select>

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