javascript - observableArray 中可观察值的 knockout 计算

Question

是否可以在 observableArray 中包含一个对象，该对象是同一对象中其他可观察对象的计算值？我有以下数组:

self.drug_costs_table = ko.observableArray([
        {
            label: ko.observable('salad'),
            cost_per_dose: ko.observable('123'),
            administrations: ko.observable('9'),
            discount: ko.observable('10'),
            cost_per_year: ko.computed(function () {
                // administrations * cost per dose
            })
        }
]);

observableArray 将在 HTML 中动态构建，最后一列是药物成本 x 管理。是否可以在数组中包含该值，或者是否必须在数组之外执行某些操作来计算 cost_per_year？

这是我的 HTML:

<!-- ko foreach: drug_costs_table -->
    <div class="row">
        <div class="grid_4"><label data-bind="text: label"></label></div>
        <div class="grid_2"><input class="total-val" data-bind="decimal: cost_per_dose"></div>
        <div class="grid_2"><input data-bind="number: administrations"></div>
        <div class="grid_2"><input data-bind="percentage: discount"></div>
        <div class="grid_2"><input class="total-val" data-bind="decimal: cost_per_year"></div>
    </div>
<!-- /ko -->

对此的任何帮助/建议将不胜感激；我对于 knockout 还是个新手!

fiddle :http://jsfiddle.net/VWc8e/

Answer 1

这是可能的。但我认为您最好为药品成本实体定义一个 View 模型。

function drugCot(label, cost_per_does, administrations, discount) {
   var self = this;
    self.label = ko.observable(label),
    self.cost_per_dose = ko.observable(cost_per_does),
    self.administrations = ko.observable(administrations),
    self.discount = ko.observable(discount),
    self.cost_per_year = ko.computed(function () {
         return  self.administrations() *  self.cost_per_year();
    })
}

然后您可以在包含 self.drug_costs_table 的 View 模型内部使用它来添加新成本。

self.durg_costs_table.push(new drugCost('salad', 123, 9, 10));

编辑

每当您现在更新 self.administrations 或 self.cost_per_year 可观测值时，您计算的 cost_per_year 都会更新。

var drugCost1 = new drugCost('salad', 123, 9, 10);
self.durg_costs_table.push(drugCost1);
drugCost1.administrations(15);
// after this line of code cost_per_year will contian new value and will notify all the subscribers and rerender bound html elements