Question

我有两个模型，一个与另一个具有hasMany关系：

配送费：

import DS from 'ember-data';

export default DS.Model.extend({
  pickup_address: DS.belongsTo('address', { inverse: null }),
  delivery_address: DS.belongsTo('address', { inverse: null }),
  shipment_lines: DS.hasMany('shipment-line', { inverse: null }),
  shipmentPrice: Ember.computed('shipment_lines.@each.package_price', function () {
    let price = 0;
    this.get('shipment_lines').forEach(function(shipment_line) {
      price += Number(shipment_line.get('package_price'));
    });
    return price;
  }),
});

和装运线型号：

import DS from 'ember-data';

export default DS.Model.extend({
    description: DS.attr('string'),
    package_weight: DS.attr('number'),
    package_length: DS.attr('number'),
    package_width: DS.attr('number'),
    package_height: DS.attr('number'),
    package_price: DS.attr('number'),
});

在控制器中，当我向货件添加新的装运行时，我从API获取包裹的价格并将其添加到装运行：

addShipmentLine(shipmentLine) {
  // Get price for shipment line
  this.getShipmentLinePrice(shipmentLine);

  // Add shipment line to shipment
  let shipment = this.get('shipment');
  shipment.get('shipment_lines').addObject(shipmentLine);
},

getShipmentLinePrice函数（简化）：

getShipmentLinePrice(shipmentLine) {
    ...
    // Get weight and type
    let weight = shipmentLine.get('package_weight');
    let length = shipmentLine.get('package_length');
    let height = shipmentLine.get('package_height');
    let width  = shipmentLine.get('package_width');

    // Fetch price from API
    this.get('price').getPackagePrice(weight, length, height, width).then(
        (price) => {
            shipmentLine.set('package_price', price['price']);
        }
    );
}

最后，当我尝试在模板中打印shipmentPrice时，它不会更新。即使价格是从服务器返回的，并且设置了shipment_line s package_price。

此外，当我使用shipment.save();保存货件并且路线被重定向到展示页面时，价格会翻倍，直到我刷新页面。页面刷新后，一切都正确显示。

所以第一个问题是，在添加新的装运线对象时，如何让装运计算属性shipmentPrice更新？或者是不可能的？

第二个问题是，为什么保存后价格会翻倍？

Answer 1

尝试：

shipmentPrice: Ember.computed('shipment_lines.[]', function () {
    let price = 0;
    this.get('shipment_lines').forEach(function(shipment_line) {
       price += Number(shipment_line.get('package_price'));
    });
    return price;
}),

Answer 2

我终于想到了这一个。好吧，至少我找到了解决方法。保存模型后，我手动将shipmentPrice重置为0：

freight_order.save().then(
    (new_freight_order) => {
        shipment.set('shipmentPrice', 0);
        this.transitionToRoute('shipments.show', new_freight_order.id);
    }
);

我猜服务器响应由于某种原因被添加到计算值中。

Ember Computed Property on hasMany关系未更新，并且在保存时加倍

2 个答案: