ExtJS：如何将存储字段映射到 JSON 属性？

Question

我有以下 JSON 数据：

{
  "disclaimer": "Exchange rates provided for informational purposes only and do not constitute financial advice of any kind. Although every attempt is made to ensure quality, no guarantees are made of accuracy, validity, availability, or fitness for any purpose. All usage subject to acceptance of Terms: https://openexchangerates.org/terms/",
  "license": "Data sourced from various providers; resale prohibited; no warranties given of any kind. All usage subject to License Agreement: https://openexchangerates.org/license/",
  "timestamp": 1475110853,
  "base": "USD",
  "rates": {
    "AED": 3.672983,
    "AFN": 66.5538,
    "ALL": 122.0421,
    "AMD": 473.5925,
    "ANG": 1.7763,
    "AOA": 165.571834,
    "ARS": 15.3169,
    "AUD": 1.299338,
    "AWG": 1.792667,
    "YER": 250.130999,
    "ZAR": 13.61321,
    "ZMK": 5252.024745,
    "ZMW": 9.831204,
    "ZWL": 322.387247
  }
}

我的模型定义如下：

Ext.define('CurrencyConvert.model.CurrencyCode', {
    extend : 'Ext.data.Model',
    fields : [
        {
            name : 'code',
            value : 'string'
        },
        {
            name : 'rate',
            value : 'float'
        }
    ]
});

这样我就可以获得货币代码（即“USD”）和汇率。但问题是货币代码本身就是实际汇率的属性名称；那么我将如何创建我的商店以便在我的模型中同时获得代码和费率？

例如： 对于"AED": 3.672983，我希望code 值保持“AED”，rate 字段保持 3.672983。

Answer 1

你可以这样做：

Ext.define('CurrencyConvert.model.CurrencyCode', { 扩展：'Ext.data.Model'， 字段：[ { 名称：'代码'， 值：'字符串'， 转换：函数（v，rec）{ === 在此处添加您的逻辑 === } }, { 名称：'率'， 值：'浮动' 转换：函数（v，rec）{ === 在此处添加您的逻辑 === } } ] });

Answer 2

Ext.define('CurrencyConvert.model.CurrencyCode', {
    extend : 'Ext.data.Model',
    fields : [
        {
            name : 'code',
            value : 'string'
        },
        {
            name : 'rate',
            value : 'float', 
            convert : function(value, record) {
                return jsonData.rates[record.get('code')]
            }
        }
    ]
});