参考：
http://www.cnblogs.com/TomXu/archive/2011/11/21/2257154.html
http://knockoutjs.com/documentation/introduction.html
复习：AngularJS的数据绑定
- 显示文本
<p>{{greeting}}</p>
<!-- 或者 -->
<p ng-bind=”greeting”></p>
- 表单输入
<form ng-controller=”SomeController”>
<input type=”checkbox” ng-model=”youCheckedIt”>
</form>
- 列表
<ul ng-controller=’StudentController’>
<li ng-repeat=’student in students’>
<a href=’/student/view/{{student.id}}’>{{student.name}}</a>
</li>
</ul>
- 表格
<table ng-controller=’AlbumController’>
<tr ng-repeat=’track in album’>
<td>{{$index+1}}</td>
<td>{{track.name}}</td>
<td>{{track.duration}}</td>
</tr>
</table>
使用$watch监控数据模型的变化
Knockout基础学习
示例代码出现错误，显示jquery-tmpl版本太久，参考解决办法。jquery.tmpl.js的下载地址：
https://raw.githubusercontent.com/BorisMoore/jquery-tmpl/master/jquery.tmpl.js
https://github.com/BorisMoore/jquery-tmpl
库的在线引用地址：
<script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript" src="./jquery.tmpl.js"></script>
<script type="text/javascript" src="http://knockoutjs.com/downloads/knockout-latest.js"></script>
入门
重要概念：
- 声明式绑定
- UI界面自动刷新
- 依赖跟踪
- 模板
启用绑定
ko.applyBindings(viewModel)
数据模型
var viewModel = {
chosenMeal: ko.observable(availableMeals[0])
}
数据
var availableMeals = [
{ mealName: 'Standard', description: 'Dry crusts of bread', extraCost: 0 },
{ mealName: 'Premium', description: 'Fresh bread with cheese', extraCost: 9.95 },
{ mealName: 'Deluxe', description: 'Caviar and vintage Dr Pepper', extraCost: 18.50 }
];
使用绑定，写变量
Chosen meal: <select data-bind="options: availableMeals,
optionsText: 'mealName',
value: chosenMeal"></select>
使用绑定，读变量，并作为参数提供给函数
<p>
You've chosen:
<b data-bind="text: chosenMeal().description"></b>
(price: <span data-bind='text: formatPrice(chosenMeal().extraCost)'></span>)
</p>
<script>
function formatPrice(price) {
return price == 0 ? "Free" : "$" + price.toFixed(2);
}
</script>
Observables 可观察变量
概念
observables, Dependent Observables, Observable Array
核心功能
observables 可观察变量 Dependency tracking 依赖跟踪
declarative bindings 显式绑定
templating 模板
View-Model 视图模型
激活Knockout
ko.applyBindings(myViewModel, document.getElementById('someElementId'))
可观察变量，声明
var myViewModel = {
personName: ko.observable('Bob'),
personAge: ko.observable(123)
};
可观察变量，读写
读：myViewModel.personAge()
写：myViewModel.personName(‘Mary’)，支持链式语法
绑定，data-bind，注册到可观察变量
可观察变量，显示订阅
var subscription = myViewModel.personName.subscribe(function (newValue) { /* do stuff */ });
// ...then later...
subscription.dispose(); // I no longer want notifications
依赖可观察变量
var viewModel = {
firstName: ko.observable('Bob'),
lastName: ko.observable('Smith')
};
viewModel.fullName = ko.dependentObservable(function () {
return this.firstName() + " " + this.lastName();
}, viewModel);
从依赖变量写入可观察变量
viewModel.fullName = ko.dependentObservable({ read: function () {
return this.firstName() + " " + this.lastName();
}, write: function (value) {
var lastSpacePos = value.lastIndexOf(" ");
if (lastSpacePos > 0) { // Ignore values with no space character
this.firstName(value.substring(0, lastSpacePos)); // Update "firstName"
this.lastName(value.substring(lastSpacePos + 1)); // Update "lastName"
}
},
owner: viewModel
});
使用依赖变量数组observable array
var myObservableArray = ko.observableArray(); // Initially an empty array
myObservableArray.push('Some value'); // Adds the value and notifies observers// This observable array initially contains three objects
var anotherObservableArray = ko.observableArray([
{ name: "Bungle", type: "Bear" },
{ name: "George", type: "Hippo" },
{ name: "Zippy", type: "Unknown" }
]);
js等价读取信息：length, indexOf, slice
js数组等价操作：pop, push, shift, unshift, reverse, sort, splice
特殊操作：remove, removeAll
绑定语法一
visible: 绑定到DOM元素，控制元素是否显示
text: 控制元素的文本值
html: 控制元素显示的HTML值
css: 添加或删除一个或多个CSS class到DOM元素上
style: 添加或删除一个或多个DOM元素上的style值
attr: 提供了一种方式可以设置DOM元素的任何属性值
绑定语法二
click
event, 例如keypress, mouseover, mouseout
submit
enable
disable
绑定语法三
value, <input>, <select>, <textarea>
checked, <input type=’checkbox’>, <input type=’radio’>
options, <select>, <select size=’6’>
selectedOptions, multi-select
uniqueName
模板绑定
使用jquery.tmpl，你可以使用任何你模板引擎支持的语法。jquery.tmpl执行如下语法：
${ someValue } — 参考文档
{{html someValue}} — 参考文档
{{if someCondition}} — 参考文档
{{else someCondition}} — 参考文档
{{each someArray}} — 参考文档
创建自定义绑定
创建自定义绑定要在ko.bingdinghandlers中注册你的绑定名称，完成初始动作和更新动作
ko.bindingHandlers.yourBindingName = {
init: function(element, valueAccessor, allBindingsAccessor, viewModel) {
// This will be called when the binding is first applied to an element
// Set up any initial state, event handlers, etc. here
}, update: function(element, valueAccessor, allBindingsAccessor, viewModel) {
// This will be called once when the binding is first applied to an element,
// and again whenever the associated observable changes value.
// Update the DOM element based on the supplied values here.
}
};
例如，我一般通过visible绑定控制一个元素的可见性，但是你希望更进一步能够动画显示这种转换。你希望元素根据一个绑定值slide in和slide out，你可以自定义一个绑定，在其中使用jQuery的 slideUp/slideDown功能。
ko.bindingHandlers.slideVisible = {
update: function(element, valueAccessor, allBindings) {
// First get the latest data that we're bound to
var value = valueAccessor(); // Next, whether or not the supplied model property is observable, get its current value
var valueUnwrapped = ko.unwrap(value); // Grab some more data from another binding property
var duration = allBindings.get('slideDuration') || 400; // 400ms is default duration unless otherwise specified // Now manipulate the DOM element
if (valueUnwrapped == true)
$(element).slideDown(duration); // Make the element visible
else
$(element).slideUp(duration); // Make the element invisible
}
};
这样使用绑定：
<div data-bind="slideVisible: giftWrap, slideDuration:600">You have selected the option</div>
<label><input type="checkbox" data-bind="checked: giftWrap" /> Gift wrap</label><script type="text/javascript">
var viewModel = {
giftWrap: ko.observable(true)
};
ko.applyBindings(viewModel);
</script>
加载或保存JSON数据
加载或保存数据：例如使用jQuery的$.getJSON, $.post, $.ajax
转化ViewModel数据到JSON格式，有时需要json2.js类库
ko.toJS 转化为JS对象
ko.toJSON 转化为JSON字符串
使用JSON更新ViewModel数据
手动方式
// 载入冰解析JSON
var someJSON = /* 使用你期望的任何方法获取JSON */
var parsed = JSON.parse(someJSON);// 更新view model属性
viewModel.firstName(parsed.firstName);
viewModel.pets(parsed.pets);
或者使用 knockout.mapping
使用Mapping插件
var viewModel = ko.mapping.fromJS(data); //创建ViewModel
ko.mapping.fromJS(data, viewModel); //更新ViewModel
用法：
key, create, update, ignore, include, copy
两种方式创建viewModel
var viewModel = {
firstName: ko.observable("Planet"),
lastName: ko.observable("Earth")
};viewModel.fullName = ko.dependentObservable({ read: function() {
return this.firstName() + " " + this.lastName();
}, write: function(value) {
var lastSpacePos = value.lastIndexOf(" ");
if (lastSpacePos > 0) { // Ignore values with no space character
this.firstName(value.substring(0, lastSpacePos)); // Update "firstName"
this.lastName(value.substring(lastSpacePos + 1)); // Update "lastName"
}
},
owner: viewModel
});
var clickCounterViewModel = function() {
this.numberOfClicks = ko.observable(0); this.registerClick = function() {
this.numberOfClicks(this.numberOfClicks() + 1);
} this.hasClickedTooManyTimes = ko.dependentObservable(function() {
return this.numberOfClicks() >= 3;
}, this);
};ko.applyBindings(new clickCounterViewModel());
应用举例
常用的控件
源代码：视图
<div class="readout">
<h3>What's in the model?</h3>
<table>
<tr>
<td class="label">Text value:</td>
<td data-bind="text: stringValue"></td>
</tr>
<tr>
<td class="label">Password:</td>
<td data-bind="text: passwordValue"></td>
</tr>
<tr>
<td class="label">Bool value:</td>
<td data-bind='text: booleanValue() ? "True" : "False"'></td>
</tr>
<tr>
<td class="label">Selected option:</td>
<td data-bind="text: selectedOptionValue"></td>
</tr>
<tr>
<td class="label">Multi-selected options:</td>
<td data-bind="text: multipleSelectedOptionValues"></td>
</tr>
<tr>
<td class="label">Radio button selection:</td>
<td data-bind="text: radioSelectedOptionValue"></td>
</tr>
</table>
</div><h3>HTML controls</h3>
<table>
<tr>
<td class="label">Text value (updates on change):</td>
<td><input data-bind="value: stringValue" /></td>
</tr>
<tr>
<td class="label">Text value (updates on keystroke):</td>
<td><input data-bind='value: stringValue, valueUpdate: "afterkeydown"' /></td>
</tr>
<tr>
<td class="label">Text value (multi-line):</td>
<td><textarea data-bind="value: stringValue"> </textarea></td>
</tr>
<tr>
<td class="label">Password:</td>
<td><input type="password" data-bind="value: passwordValue" /></td>
</tr>
<tr>
<td class="label">Checkbox:</td>
<td><input type="checkbox" data-bind="checked: booleanValue" /></td>
</tr>
<tr>
<td class="label">Drop-down list:</td>
<td><select data-bind="options: optionValues, value: selectedOptionValue"></select></td>
</tr>
<tr>
<td class="label">Multi-select drop-down list:</td>
<td><select multiple="multiple" data-bind="options: optionValues, selectedOptions: multipleSelectedOptionValues"></select></td>
</tr>
<tr>
<td class="label">Radio buttons:</td>
<td>
<label><input type="radio" value="Alpha" data-bind="checked: radioSelectedOptionValue" />Alpha</label>
<label><input type="radio" value="Beta" data-bind="checked: radioSelectedOptionValue" />Beta</label>
<label><input type="radio" value="Gamma" data-bind="checked: radioSelectedOptionValue" />Gamma</label>
</td>
</tr>
</table>
源代码：View Model
var viewModel = {
stringValue : ko.observable("Hello"),
passwordValue : ko.observable("mypass"),
booleanValue : ko.observable(true),
optionValues : ["Alpha", "Beta", "Gamma"],
selectedOptionValue : ko.observable("Gamma"),
multipleSelectedOptionValues : ko.observable(["Alpha"]),
radioSelectedOptionValue : ko.observable("Beta")
};
ko.applyBindings(viewModel);
