敲除数据绑定到没有 foreach 的数组

Question

 <script type="text/javascript">
    var closingCostDetailsVM = ko.mapping.fromJS(@Html.Raw(@Model.ClosingCostData.ToJson()));
    ko.applyBindings(closingCostDetailsVM, byId("closingcostdetailsform"));
    ko.watch(closingCostDetailsVM, { depth: -1 }, function(parents, child, item) {
        isClosingCostDetailsChanged = true;
    });
</script>

--HTML--

 <input type="text" class="form-control col-lg-6" data-bind="value:$data[1] && $data[1].LineDescription">
<label class="col-lg-6 control-label" data-bind="text: $data[1] && $data[1].Amount"></label>
<input type="text" class="form-control col-lg-6" data-bind="value:$data[2] && $data[2].LineDescription">
<input type="text" class="form-control col-lg-6" data-bind="value:$data[2] && $data[2].LineDescription">
<label class="col-lg-6 control-label" data-bind="text: $data[2] && $data[2].Amount"></label>
<input type="text" class="form-control col-lg-6" data-bind="value:$data[3] && $data[3].LineDescription">
<label class="col-lg-6 control-label" data-bind="text: $data[3] && $data[3].Amount"></label>

第一次 model 显示计数 = 0，因此第一次保存输入值不起作用

ko.toJSON(launchpadDetailsVM) and ko.toJS(launchpadDetailsVM)

首次显示 [] 保存