How can I detect a change to an entity's EntityState?

Question

I want to put a \"Delete\" button and a \"Cancel\" button on each row of a list of Customers. The \"Cancel\" button is disabled when a customer is \"Unchanged\". But when a

Answer 1

We found wrapping the breeze entity manager inside our own gives us nice flexibility that makes this challenge a walk in the park, especially with the hasChangesChanged event.

var EntityManager = (function () {
    function EntityManager(breezeEntityManager) {
        this.breezeEntityManager = breezeEntityManager;
        this.hasChanges = ko.observable(breezeEntityManager.hasChanges());

        // Subscribe with handler watching for EntityState changes
        this.addEntityStateChangeTracking(breezeEntityManager, this);
    }

    EntityManager.prototype.addEntityStateChangeTracking = function (bem, em) {
        if (this.entityStateTrackingToken != null) return;
        this.entityStateTrackingToken = bem.hasChangesChanged.subscribe(function (changeArgs) {
            em.hasChanges(changeArgs.hasChanges);
        });
    };
    return EntityManager;
})();

Then on your viewModels, expose the EntityManager.

var ViewModel = (function (_super) {
    __extends(ViewModel, _super);
    function ViewModel(typeName) {
        _super.call(this);
        this.type = entities.getType(typeName);
    }

    ViewModel.prototype.loadEntity = function (id) {
        this.entityManager = new breeze.EntityManager("MyManager");;
    };
    return ViewModel;
})(ViewModelBase);
exports.ViewModel = ViewModel;

Then in your Knockout UI: