KnockoutJS绑定不使用映射插件进行更新

我在Knockout中有一个视图Model，它是使用映射插件映射的。我需要这样做，因为数据（JSON对象）将使用Ajax调用从服务器检索。

我的问题是，当我修改表单时，映射的数据不会在对象中更新。。。

您还可以在以下JSFiddle中看到这一点：http://jsfiddle.net/etiennenoel/4EXSy/6/

这是我从服务器检索到的对象：

var dataContent = 
[
    {
        playerId: 2,
        playerName: "allo",
        evaluatedExercises: 
        [
            {
                id: 1,
                evaluationExerciseId: 1,
                numberOfTries: 6,
                tries: [
                    {
                    id: 0,
                    number: 0,
                    result: 0
                    }
                ]
            }       
        ]
    }
]

以下是完整的javascript视图模型：

function Try(id, number, result) {
    var self = this;
    self.id = id;
    self.number = number;
    self.result = result;
}
function ExerciseResult(id, evaluationExerciseId) {
    var self = this;
    self.id = id;
    self.evaluationExerciseId = evaluationExerciseId;
    self.tries = [];
}
function PlayerEvaluation(playerId, playerName) {
    var self = this;
    self.playerId = playerId;
    self.playerName = playerName
    self.evaluatedExercises = [];
}
function appViewModel() {
    var self = this;
    self.playersEvaluation = ko.observableArray();
    self.exportToJSON = ko.computed(function() {
        return ko.toJSON(self.playersEvaluation);
    }, this);
}
var viewModel = new appViewModel();
var dataContent = 
[
    {
        playerId: 2,
        playerName: "allo",
        evaluatedExercises: 
        [
            {
                id: 1,
                evaluationExerciseId: 1,
                numberOfTries: 6,
                tries: [
                    {
                    id: 0,
                    number: 0,
                    result: 0
                    }
                ]
            }       
        ]
    }
]
for(i = 0; i < dataContent.length; i++) {
    playerEvaluation = new PlayerEvaluation(dataContent[i].playerId, dataContent[i].playerName);
    evaluatedExercises = dataContent[i].evaluatedExercises;
    for(j = 0; j < evaluatedExercises.length; j++) {    
        exerciseResult = new ExerciseResult(evaluatedExercises[j].id, evaluatedExercises[j].evaluationExerciseId);
        tries = evaluatedExercises[j].tries;
        for(k = 0; k < tries.length; k++) {
            exerciseTry = new Try(tries[k].id, tries[k].number, tries[k].result)
            exerciseResult.tries.push(exerciseTry);
        }
        playerEvaluation.evaluatedExercises.push(exerciseResult);        
    }
   viewModel.playersEvaluation.push(playerEvaluation);
}
ko.mapping.fromJS(viewModel.playersEvaluation);
ko.applyBindings(viewModel)

此对象使用KnockoutJS:映射到html中

    <table class="table table-hover table-bordered">
     <thead> <!-- This will be generated with Twig so it is normal that is does not correspond to the data below -->
         <tr>
             <th>Nom</th>
             <th colspan="6" style="text-align:center">Élément #1</th>
         </tr>
         <tr>
             <th></th>
             <th class="try">
                 1                 
             </th>
             <th class="try">
                 2                 
             </th>
             <th class="try">
                 3                 
             </th>
             <th class="try">
                 4                 
             </th>
             <th class="try">
                 5                 
             </th>
             <th class="try">
                 6                 
             </th>  
         </tr>
    </thead>
    <tbody data-bind="foreach: playersEvaluation">
        <tr data-bind="">
            <td data-bind="text: $data.playerName">
            </td>
           <!-- ko foreach: $data.evaluatedExercises -->
            <!-- ko foreach: $data.tries -->
            <td>
                <input type="text" data-bind="value: $data.result" />
            </td>
            <!-- /ko -->
            <!-- /ko -->
        </tr>
    </tbody>
</table>

<div data-bind="text: exportToJSON()">
</div>

当我修改输入时，我希望这些更改反映在我的viewModel的self.playersEvaluation变量中。为此，我创建了一个计算的Function，它在表下面的div中显示playersEvaluation的内容。

然而，div没有得到更新，因此我得出的结论是映射一定不正确

我的映射哪里出了问题？