knockout.mapping - 将包含嵌套对象的整个对象转换为 knockout.observable答案

【问题标题】：knockout.mapping - convert whole object included nested objects to knockout.observableknockout.mapping - 将包含嵌套对象的整个对象转换为 knockout.observable
【发布时间】：2013-09-18 14:46:45
【问题描述】：

我正在使用 knockout.mapping 将我的 javascript 对象转换为可观察对象。在这个 javascript 对象内部是一个嵌套对象，这个嵌套对象正在被转换，但它位于错误的位置。因此，当我的视图尝试绑定数据时它无法绑定，因为映射已将嵌套对象移动到根目录。

JSON 数据

[
    {
        "brandName": "Knockando Single Malt Whisky",
        "categoryDescription": "Alcohol - Whisky & Bourbon",
        "dateAmended": "2008-01-28T10:05:00.000Z",
        "defaultSearchName1": "KnockandoSingleMaltWhisky",
        "defaultSearchName2": "Knockando Single Malt Whisky",
        "advertiser": {
            "activities": "Motor dealers",
            "additionalInfo": "",
            "advertiserName": "Parks of Hamilton Ltd",
            "alfRank": 3311,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "Trade as Parks Motor Group.\nAlternative email: coachhire@park.uk.com, admin@park-uk.com, Info@park.uk.com.",
            "numberOfEmployees": 1000,
            "outdoorRank": 1426,
            "pressRank": 5159,
            "radioRank": 675,
            "tVRank": 1810
        }
    },
    {
        "brandName": "Tesco Petrol/Diesel Fuel",
        "categoryDescription": "Petrol & Service Stations",
        "dateAmended": "2013-07-10T15:17:00.000Z",
        "defaultSearchName1": "TescoPetrol/DieselFuel",
        "defaultSearchName2": "Tesco Petrol/Diesel Fuel",
        "advertiser": {
            "activities": "Furnitures",
            "additionalInfo": "",
            "advertiserName": "Pine & Things Ltd",
            "alfRank": 4570,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "Trade as P&T.\nAlternative email: info@pineandthings.co.uk.",
            "numberOfEmployees": 25,
            "outdoorRank": 1426,
            "pressRank": 2851,
            "radioRank": 2449,
            "tVRank": 1810
        }
    },
    {
        "brandName": "Tesco Electrical Products",
        "categoryDescription": "Supermarkets & Multiple Retailers",
        "dateAmended": "2013-07-10T15:52:00.000Z",
        "defaultSearchName1": "TescoElectricalProducts",
        "defaultSearchName2": "Tesco Electrical Products",
        "advertiser": {
            "activities": "Bridalwear",
            "additionalInfo": "",
            "advertiserName": "Phil Collins Bridal Collection Ltd",
            "alfRank": 4094,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "Alternative email: enquiries@philcollinsbridal.co.uk, pcbridal@aol.com.",
            "numberOfEmployees": 30,
            "outdoorRank": 1426,
            "pressRank": 2487,
            "radioRank": 2449,
            "tVRank": 1810
        }
    },
    {
        "brandName": "Tesco Bank Insurance Ranges",
        "categoryDescription": "Insurance Ranges",
        "dateAmended": "2012-01-05T12:30:00.000Z",
        "defaultSearchName1": "TescoBankInsuranceRanges",
        "defaultSearchName2": "Tesco Bank Insurance Ranges",
        "advertiser": {
            "activities": "Nutition supplements",
            "additionalInfo": "",
            "advertiserName": "PhD Nutrition Ltd",
            "alfRank": 4107,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "Alternative email: info@phd-supplements.com.\nThere is no alternative head office landline number.",
            "numberOfEmployees": 30,
            "outdoorRank": 1426,
            "pressRank": 2500,
            "radioRank": 2449,
            "tVRank": 1810
        }
    },
    {
        "brandName": "Tesco Clubcard",
        "categoryDescription": "Loyalty & Incentive Schemes",
        "dateAmended": "2008-03-26T14:05:00.000Z",
        "defaultSearchName1": "TescoClubcard",
        "defaultSearchName2": "Tesco Clubcard",
        "advertiser": {
            "activities": "",
            "additionalInfo": "",
            "advertiserName": "British Regional Airlines Group PLC",
            "alfRank": 6031,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "",
            "numberOfEmployees": 0,
            "outdoorRank": 1426,
            "pressRank": 5159,
            "radioRank": 2449,
            "tVRank": 1810
        }
    },
    {
        "brandName": "Royal Mail Corporate",
        "categoryDescription": "Public Services - Corporate",
        "dateAmended": "2010-06-04T11:45:00.000Z",
        "defaultSearchName1": "RoyalMailCorporate",
        "defaultSearchName2": "Royal Mail Corporate",
        "advertiser": {
            "activities": "",
            "additionalInfo": "",
            "advertiserName": "Yorkshire Power Group Ltd",
            "alfRank": 6031,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "",
            "numberOfEmployees": 0,
            "outdoorRank": 1426,
            "pressRank": 5159,
            "radioRank": 2449,
            "tVRank": 1810
        }
    },
    {
        "brandName": "E.ON Surf & Save ISP",
        "categoryDescription": "Telecom - Internet Service Providers",
        "dateAmended": "2007-11-23T12:25:00.000Z",
        "defaultSearchName1": "E.ONSurf&SaveISP",
        "defaultSearchName2": "E.ON Surf & Save ISP",
        "advertiser": {
            "activities": "",
            "additionalInfo": "",
            "advertiserName": "Stagecoach Ltd",
            "alfRank": 6031,
            "cinemaRank": 286,
            "directMailRank": 1291,
            "internetRank": 1988,
            "notes": "",
            "numberOfEmployees": 0,
            "outdoorRank": 1426,
            "pressRank": 5159,
            "radioRank": 2449,
            "tVRank": 1810
        }
    }
]

Javascript

 // Get JSON from local storage and convert to js object
 var objBrands = new Object(ko.mapping.fromJSON(localStorage.getItem('Brands')));

 // Convert from object to observable
 brands = ko.mapping.fromJS(objBrands)

我的对象在转换为 observable 之前的数据

转换后

在屏幕截图二中 - 广告客户在错误的位置。我希望它在 [0] 内，但 ko.mapping 解析了我的对象并将其放在那里。

【问题讨论】：

你能写一个关于问题是什么，你尝试了什么等等的解释吗？
@PWKad 当然。我会更新我的问题。
@PWKad 嘿，我尽我所能解释了。如果您查看我的屏幕截图，您可以看到广告客户在对象内的位置。使用 ko.mapping 后它在错误的位置。
所以这对我来说没有任何意义，它是 [0] 内的嵌套 observable，只是顺序不同？如果您要调用 observableArray 的任何名称，例如 myArray()[0].advertisers()，您会得到一个广告商列表，至少我是怎么看的。如果您得到一个对象不是函数错误，这意味着您正在正确映射子属性，但是使用您的代码，我无法判断 --- 您没有映射子对象，请参见下面的链接
KO Mapping issue with child objects 的可能重复项

标签： knockout.js knockout-mapping-plugin

【解决方案1】：

这是你今天的香蕉。

您可以做几件事，但我将向您指出使用 ko.mapping 插件的方向。这是我以您的情况为例拟定的小提琴。

http://jsfiddle.net/beauxjames/ps75V/

首先你会看到你的数据，我确实添加了一个小的 json 对象值来启动并将它加载到一个局部变量中::

var rawData = { "brand": [
{...} ]};

接下来，我们有 jQuery、knockout.js 和 knockout.mapping.js。

然后，注意函数类型::

var BrandsViewModel = function(data) {
    var self = this;
    ko.mapping.fromJS(data, brandMapping, self);
}

var AdvertiserViewModel = function(data) {
    var self = this;
    ko.mapping.fromJS(data, {}, self);
}

现在，每个内部都有一个 ko.mapping.fromJS() 的声明...这里有详细解释 :: http://knockoutjs.com/documentation/plugins-mapping.html

然后是映射本身::

var brandMapping = {
    'brands': {
        create: function (options) {
            if (options.data != null) return new BrandsViewModel(options.data);
        }
    },
    'advertiser': {
        create: function (options) {
            if (options.data != null) return new AdvertiserViewModel(options.data);
        }
    }
}

然后……业务结束::

$(document).ready(function() {
    var viewModel = new BrandsViewModel(rawData);
    ko.applyBindings(viewModel, document.getElementById('mylist'));
});

如您所见...将这些复杂的对象映射到可观察对象确实是使用这个插件非常简单的事情。一切都捆绑在一起，您可以将其推送到任何类型的可编辑环境并发疯……一切都在那里，您可以直接从 XXXViewModel 的声明中扩展您的模型，并且对象的每个实例都会变得越来越智能.

希望这有帮助！

【讨论】：