在事件回调中更新模型时，更新模型属性对视图没有影响，有什么解决方法吗？

这是我的服务：

angular.service('Channel', function() {        
    var channel = null; 

    return {        
        init: function(channelId, clientId) {
            var that = this;        

            channel = new goog.appengine.Channel(channelId);
            var socket = channel.open();

            socket.onmessage = function(msg) {
                var args = eval(msg.data);              
                that.publish(args[0], args[1]);
            };
        }       
    };
});

publish() 功能是在控制器中动态添加的。

控制器：

App.Controllers.ParticipantsController = function($xhr, $channel) {
    var self = this;

    self.participants = [];     

    // here publish function is added to service
    mediator.installTo($channel); 

    // subscribe was also added with publish        
    $channel.subscribe('+p', function(name) { 
        self.add(name);     
    });                 

    self.add = function(name) {     
        self.participants.push({ name: name });     
    }
};

App.Controllers.ParticipantsController.$inject = ['$xhr', 'Channel'];

看法：

<div ng:controller="App.Controllers.ParticipantsController">      
    <ul>
        <li ng:repeat="participant in participants"><label ng:bind="participant.name"></label></li>
    </ul>

    <button ng:click="add('test')">add</button>
</div>

所以问题是点击按钮会正确更新视图，但是当我从 Channel 收到消息时什么也没发生，甚至add()调用了该函数