Unable to parse bindings js error using ko.mapping.fromJSON with parse exists view model

Question

我想以 JSON 格式将视图模型保存在隐藏字段中。一切正常。

但是当我尝试获取它时 - 我得到了错误：

未捕获的错误：无法解析绑定。 消息：ReferenceError：selectAll 未定义； 绑定值：选中：AllCheck，单击：selectAll

JsFiddler

视图模型

function AppViewModel() {

//Week
this.AllCheck = ko.observable(false);
this.DaysOfWeekResult = ko.observableArray();

this.selectAll = function () {
    if (this.AllCheck()) {
        viewModel.DaysOfWeekResult.removeAll();

        viewModel.DaysOfWeekResult.push("Mo");
        viewModel.DaysOfWeekResult.push("Tu");
        viewModel.DaysOfWeekResult.push("We");
        viewModel.DaysOfWeekResult.push("Th");
        viewModel.DaysOfWeekResult.push("Fr");
        viewModel.DaysOfWeekResult.push("Sa");
        viewModel.DaysOfWeekResult.push("Su");
    }

    return true;
};

    this.dayClicked = function () {
    checkDays();
    return true;
};        

}

初始化代码

var viewModel;    
$().ready(function (){
        viewModel = new AppViewModel();
var viewModelDeserialized = ko.mapping.fromJSON(serializedJsonString, viewModel);

        ko.applyBindings(viewModel);
}); 


function checkDays() {
    viewModel.AllCheck(viewModel.DaysOfWeekResult().length == 7);   
}  

序列化模型

var serializedJsonString = '"AllCheck":false,"DaysOfWeekResult":[]}';

标记

<div class="check-block">
                <input name="AllWeek" id="AllWeek" type="checkbox" value="AllWeek" data-bind="checked: AllCheck, click: selectAll" />
                <label for="AllWeek">All Week</label>
            </div>
            <div class="holder">
                <span>
                    <input name="Monday" id="Monday" type="checkbox" value="Mo" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Monday">Mo</label>
                </span><span>
                    <input name="Tuesday" id="Tuesday" type="checkbox" value="Tu" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Tuesday">Tu</label>
                </span><span>
                    <input name="Wednesday" id="Wednesday" type="checkbox" value="We" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Wednesday">We</label>
                </span>               
                <span>
                    <input name="Thursday" id="Thursday" type="checkbox" value="Th" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Thursday">Th</label>
                </span><span>
                    <input name="Friday" id="Friday" type="checkbox" value="Fr" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Friday">Fr</label>
                </span><span>
                    <input name="Saturday" id="Saturday" type="checkbox" value="Sa" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Saturday">Sa</label>
                </span><span>
                    <input name="Sunday" id="Sunday" type="checkbox" value="Su" data-day="true" data-bind="checked: DaysOfWeekResult, click: dayClicked" />
                    <label for="Sunday">Su</label>
                </span>
            </div>

​

Answer 1

您使用错误的参数调用ko.mapping.fromJSON。

在您的情况下正确用法如下：

var viewModelDeserialized = 
    ko.mapping.fromJSON(serializedJsonString, {} /* empty options */, viewModel);

Demo fiddle.（没有绑定错误）

ko.mapping.fromJSON 方法的使用有点棘手：

• 您可以使用一个参数调用它：只提供数据，例如var viewModel = ko.mapping.fromJSON(data)，在这种情况下，它将返回创建的视图模型

• 你可以用两个参数调用：

  • 如果第二个参数是一个 ko 映射创建的视图模型，那么它被视为映射目标ko.mapping.fromJSON(data, koMappingCreatedViewModel)
  • 否则第二个参数将被视为映射选项（在您的情况下会发生这种情况）var viewModel = ko.mapping.fromJSON(data, options)

• 您可以使用三个参数显式指定数据、映射和目标来调用它：ko.mapping.fromJSON(data, options, target)