diff --git a/public/_data.json b/public/_data.json index 6427634fc8..0fbe22cf6c 100644 --- a/public/_data.json +++ b/public/_data.json @@ -1,8 +1,8 @@ { "index": { "hero": "home", - "title": "一个框架", - "subtitle": "适用于手机与桌面" + "title": "一套框架,多个平台", + "subtitle": "同时适用手机与桌面" }, "features": { diff --git a/public/docs/ts/latest/guide/dependency-injection.jade b/public/docs/ts/latest/guide/dependency-injection.jade index c2cfd5861e..71e35a7860 100644 --- a/public/docs/ts/latest/guide/dependency-injection.jade +++ b/public/docs/ts/latest/guide/dependency-injection.jade @@ -7,33 +7,53 @@ include ../_util-fns we really can't build an Angular application without it. It's used so widely that almost everyone just calls it _DI_. + **依赖注入** 是一个很重要的程序设计模式。 + Angular有自己的依赖注入框架,离开了它,我们几乎没法构建Angular应用。 + 它使用的是如此广泛,以至于几乎每个人都会把它简称为 _DI_ 。 + In this chapter we'll learn what DI is and why we want it. Then we'll learn [how to use it](#angular-di) in an Angular app. + + 在本章中,我们将学习DI是什么,以及为什么我们需要它。 + 然后,我们将学习在Angular应用中该[如何使用它](#angular-di)。 // #enddocregion intro :marked [Run the live example](/resources/live-examples/dependency-injection/ts/plnkr.html) + + [运行鲜活范例](/resources/live-examples/dependency-injection/ts/plnkr.html) // #docregion why-1 .l-main-section :marked ## Why dependency injection? + ## 为什么需要依赖注入? Let's start with the following code. + + 我们从下列代码开始: // #enddocregion why-1 -+makeExample('dependency-injection/ts/app/car/car-no-di.ts', 'car', 'app/car/car.ts (without DI)') ++makeExample('dependency-injection/ts/app/car/car-no-di.ts', 'car', 'app/car/car.ts (没有 DI)') // #docregion why-2 - var lang = current.path[1] - var prefix = lang == 'dart' ? '' : 'this.' :marked Our `Car` creates everything it needs inside its constructor. What's the problem? + + 我们的`Car`类会在它的构造函数中亲自创建所需的每样东西。 + 问题何在? The problem is that our `Car` class is brittle, inflexible, and hard to test. + + 问题是,我们这个`Car`类过于脆弱、缺乏弹性并且难以测试。 Our `Car` needs an engine and tires. Instead of asking for them, the `Car` constructor creates its own copies by "new-ing" them from the very specific classes, `Engine` and `Tires`. + 我们的汽车(`Car`)类需要一个引擎(`Engine`)和轮胎(`Tires`),它没有去请求一个现成的实例, + 而是在构造函数中用具体的类`Engine`和`Tires`新创建了一份只给自己用的副本。 + What if the `Engine` class evolves and its constructor requires a parameter? Our `Car` is broken and stays broken until we rewrite it along the lines of `#{prefix}engine = new Engine(theNewParameter)`. @@ -42,52 +62,89 @@ include ../_util-fns But we'll *have* to start caring because when the definion of `Engine` changes, our `Car` class must change. That makes `Car` brittle. + + 如果`Engine`类升级了,并且它的构造函数要求传入一个参数了怎么办? + 我们这个`Car`类就被破坏了,并且直到我们把创建代码重写为`#{prefix}engine = new Engine(theNewParameter)`之前,它都坏着。 + 当我们首次写`Car`类时,我们不会在乎`Engine`构造函数的参数。其实现在我们也不想在乎。 + 但当`Engine`类的定义发生变化时,我们就不得不在乎了,`Car`类也不得不跟着改变。 + 这就会让`Car`类过于脆弱。 What if we want to put a different brand of tires on our `Car`? Too bad. We're locked into whatever brand the `Tires` class creates. That makes our `Car` inflexible. + + 如果我们想在我们的`Car`上用一个不同品牌的轮胎会怎样?太糟了。 + 我们被锁死在了`Tires`类创建时使用的那个品牌上。这让我们的`Car`类缺乏弹性。 Right now each new car gets its own engine. It can't share an engine with other cars. While that makes sense for an automobile engine, we can think of other dependencies that should be shared, such as the onboard wireless connection to the manufacturer's service center. Our `Car` lacks the flexibility to share services that have been created previously for other consumers. + + 现在,每辆车都有它自己的引擎。它不能和其它车辆共享引擎。 + 虽然这对于汽车来说还算可以理解,但是我们设想一下那些应该被共享的依赖,比如到厂家服务中心的车载无线(译注:汽车的一种设备,用于联系厂家)。 + 我们的车缺乏必要的弹性,来共享当初给其他消费者创建的车载无线。 When we write tests for our `Car` we're at the mercy of its hidden dependencies. Is it even possible to create a new `Engine` in a test environment? What does `Engine`itself depend upon? What does that dependency depend on? Will a new instance of `Engine` make an asynchronous call to the server? We certainly don't want that going on during our tests. + + 当我们给`Car`类写测试的时候,我们得自己摆弄它那些隐藏的依赖。 + 你以为能在测试环境中成功创建一个新的`Engine`吗? + `Engine`自己又依赖什么?那些依赖本身又依赖什么? + `Engine`的新实例会发起一个到服务器的异步调用吗? + 我们当然不想在测试期间这么一层层追下去。 What if our `Car` should flash a warning signal when tire pressure is low? How do we confirm that it actually does flash a warning if we can't swap in low-pressure tires during the test? + + 如果我们的`Car`应该在轮胎气压低的时候闪一个警示灯该怎么办? + 如果我们没法在测试期间换上一个低气压的轮胎,我们该如何确认它确实能正确的闪警示灯? We have no control over the car's hidden dependencies. When we can't control the dependencies, a class becomes difficult to test. + + 我们没法控制这辆车背后隐藏的依赖。 + 而如果我们不能控制这些依赖,类就会变得难于测试。 How can we make `Car` more robust, flexible, and testable? + + 我们该如何让`Car`更强壮、有弹性以及可测试? That's super easy. We change our `Car` constructor to a version with DI: + + 答案超级简单。我们把`Car`的构造函数改造成使用DI的版本: // #enddocregion why-2 +makeTabs( 'dependency-injection/ts/app/car/car.ts, dependency-injection/ts/app/car/car-no-di.ts', 'car-ctor, car-ctor', - 'app/car/car.ts (excerpt with DI), app/car/car.ts (excerpt without DI)')(format=".") + 'app/car/car.ts (使用DI的代码节选), app/car/car.ts (不用DI的代码节选)')(format=".") // #docregion why-3-1 :marked See what happened? We moved the definition of the dependencies to the constructor. Our `Car` class no longer creates an engine or tires. It just consumes them. + + 发生了什么?我们把依赖的定义移到了构造函数中。 + 我们的`Car`类不再创建引擎或者轮胎。 + 它仅仅“消费”它们。(译注:指直接使用成品) // #enddocregion why-3-1 // TypeScript only .l-sub-section :marked We also leverage TypeScript's constructor syntax for declaring parameters and properties simultaneously. + + 我们还借助了TypeScript的构造语法来同时定义参数和属性。 // #docregion why-3-2 :marked Now we create a car by passing the engine and tires to the constructor. + + 现在,我们通过往构造函数中传入引擎和轮胎来创建一辆车。 // #enddocregion why-3-2 - var stylePattern = { otl: /(new Car.*$)/gm }; +makeExample('dependency-injection/ts/app/car/car-creations.ts', 'car-ctor-instantiation', '', stylePattern)(format=".") @@ -98,14 +155,21 @@ include ../_util-fns decoupled from the `Car` class itself. We can pass in any kind of engine or tires we like, as long as they conform to the general API requirements of an engine or tires. + + 酷!引擎和轮胎这两个依赖的定义从`Car`类本身解耦开了。 + 只要喜欢,我们就可以传入任何类型的引擎或轮胎,只要它们能满足引擎或轮胎的普遍API需求。 If someone extends the `Engine` class, that is not `Car`'s problem. + + 如果有人扩展了`Engine`类,那就不再是`Car`类的烦恼。 // #enddocregion why-4 // Must copy the following, due to indented +make. .l-sub-section :marked The _consumer_ of `Car` has the problem. The consumer must update the car creation code to something like this: + + `Car`的 _消费者_ 也有这个问题。消费者必须更新创建这辆车的代码,就像这样: - var stylePattern = { otl: /(new Car.*$)/gm }; +makeExample('dependency-injection/ts/app/car/car-creations.ts', 'car-ctor-instantiation-with-param', '', stylePattern)(format=".") @@ -113,29 +177,45 @@ include ../_util-fns :marked The critical point is this: `Car` itself did not have to change. We'll take care of the consumer's problem soon enough. + + 这里的要点是:`Car`本身不必变化。我们很快就来解决消费者的问题。 // #docregion why-6 :marked The `Car` class is much easier to test because we are in complete control of its dependencies. We can pass mocks to the constructor that do exactly what we want them to do during each test: + + `Car`类非常容易测试,因为我们现在对它的依赖有了完全的控制权。 + 我们可以往构造函数中传入mock对象,在每个测试期间,它们可以做到我们想让它们做的事: // #enddocregion why-6 - var stylePattern = { otl: /(new Car.*$)/gm }; +makeExample('dependency-injection/ts/app/car/car-creations.ts', 'car-ctor-instantiation-with-mocks', '', stylePattern)(format=".") // #docregion why-7 :marked **We just learned what dependency injection is**. + + **我们刚刚学过什么是依赖注入** It's a coding pattern in which a class receives its dependencies from external sources rather than creating them itself. + + 它是一个编程模式,该模式可以让一个类从外部源中获得它的依赖,而不必自己创建它们。 Cool! But what about that poor consumer? Anyone who wants a `Car` must now create all three parts: the `Car`, `Engine`, and `Tires`. The `Car` class shed its problems at the consumer's expense. We need something that takes care of assembling these parts for us. + + 酷!但是,可怜的消费者怎么办? + 那些希望得到一个`Car`的人们现在必须创建所有这三部分了:`Car`、`Engine`和`Tires`。 + `Car`类把它的快乐建立在了消费者的痛苦之上。 + 我们需要某种机制把这三个部分装配好。 We could write a giant class to do that: + + 我们可以写一个巨型类来做这件事: // #enddocregion why-7 +makeExample('dependency-injection/ts/app/car/car-factory.ts', null, 'app/car/car-factory.ts') // #docregion why-8 @@ -144,15 +224,27 @@ include ../_util-fns But maintaining it will be hairy as the application grows. This factory is going to become a huge spiderweb of interdependent factory methods! + + 现在只需要三个创建方法,这还不算太坏。 + 但是当应用规模变大之后,维护它将变得惊险重重。 + 这个工厂类将变成一个由相互依赖的工厂方法构成的矩形蜘蛛网。 Wouldn't it be nice if we could simply list the things we want to build without having to define which dependency gets injected into what? + + 如果我们能简单的列出我们想建造的东西,而不用定义要把哪些依赖注入哪些对象,是不是会很美妙? This is where the dependency injection framework comes into play. Imagine the framework had something called an _injector_. We register some classes with this injector, and it figures out how to create them. + + 到了让依赖注入框架一展身手的时候了! + 想象框架中有一个叫做 _注入器(injector)_ 的东西。 + 我们使用这个注入器注册一些类,还会指出该如何创建它们。 When we need a `Car`, we simply ask the injector to get it for us and we're good to go. + + 当我们需要一个`Car`时,就简单的请求注入器取得它,然后直接去提车。 // #enddocregion why-8 +makeExample('dependency-injection/ts/app/car/car-injector.ts','injector-call')(format=".") // #docregion why-9 @@ -161,26 +253,43 @@ include ../_util-fns The consumer knows nothing about creating a `Car`. We don't have a gigantic factory class to maintain. Both `Car` and consumer simply ask for what they need and the injector delivers. + + 多方皆赢的方式。`Car`不需要知道如何创建`Engine`和`Tires`的任何事。 + 消费者不知道如何创建`Car`的任何事。 + 我们不需要一个巨大的工厂类来维护它们。 + `Car`和消费者只要简单的说出它们想要什么,注入器就会交付给它们。 This is what a **dependency injection framework** is all about. + + 这就是关于 **依赖注入框架** 的一切。 Now that we know what dependency injection is and appreciate its benefits, let's see how it is implemented in Angular. + + 现在,我们知道了依赖注入是什么,以及它的优点是什么。我们再来看看它在Angular中是怎么实现的。 // #enddocregion why-9 // #docregion di-1 .l-main-section :marked ## Angular dependency injection + ## Angular依赖注入 Angular ships with its own dependency injection framework. This framework can also be used as a standalone module by other applications and frameworks. + + Angular自带了它自己的依赖注入框架。此框架也能被当做独立模块用于其它应用和框架中。 That sounds nice. What does it do for us when building components in Angular? Let's see, one step at a time. + + 看起来很美。当我们在Angular中构建组件的时候,它能为我们做什么? + 让我们看看,一次一步儿。 We'll begin with a simplified version of the `HeroesComponent` that we built in the [The Tour of Heroes](../tutorial/). + + 我们从曾在[英雄指南](../tutorial/)中构建过的`HeroesComponent`的一个简化版本开始。 // #enddocregion di-1 +makeTabs( `dependency-injection/ts/app/heroes/heroes.component.1.ts, @@ -198,6 +307,9 @@ include ../_util-fns It governs all the child components of this area. Our stripped down version has only one child, `HeroListComponent`, which displays a list of heroes. + + `HeroesComponent`是 *英雄* 特性分区中的根组件。它管理着本分区的所有子组件。 + 我们简化后的版本只有一个子组件`HeroListComponent`,它显示一个英雄列表。 // #enddocregion di-2 // #docregion di-3 :marked @@ -207,19 +319,29 @@ include ../_util-fns As soon as we try to test this component or want to get our heroes data from a remote server, we'll have to change the implementation of `heroes` and fix every other use of the `HEROES` mock data. + + 现在`HeroListComponent`从`HEROES`获得英雄数据,一个在另一个文件中定义的内存数据集。 + 它在开发的早期阶段可能还够用,但离完美就差得远了。 + 一旦我们开始测试此组件,或者想从远端服务器获得英雄数据,我们将不得不修改`heroes`的实现,并要修改每个用到了`HEROES`模拟数据的地方。 Let's make a service that hides how we get hero data. + + 我们来制作一个服务,来把获取英雄数据的代码封装起来。 // #enddocregion di-3 // Unnecessary for Dart .l-sub-section :marked Write this service in its own file. See [this note](#forward-ref) to understand why. + + 把这个服务写在一个独立的文件中。参见[这里的说明](#forward-ref)来理解为什么要这样。 +makeExample('dependency-injection/ts/app/heroes/hero.service.1.ts',null, 'app/heroes/hero.service.ts' ) // #docregion di-4 :marked Our `HeroService` exposes a `getHeroes` method that returns the same mock data as before, but none of its consumers need to know that. + + 我们的`HeroService`暴露了`getHeroes`方法,用于返回跟以前一样的模拟数据,但是它的消费者不需要了解这一点。 // #enddocregion di-4 // #docregion di-5 .l-sub-section @@ -230,70 +352,110 @@ include ../_util-fns [ES2015 promises](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise). We'd also have to rewrite the way components consume our service. This is important in general, but not to our current story. + + 我们甚至不能说这是一个真实的服务。 + 如果我们真的从一个远端服务器获取数据,这个API必须是异步的,可能得返回 + [ES2015 承诺(Promise)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)。 // #enddocregion di-5 // #docregion di-6 :marked A service is nothing more than a class in Angular 2. It remains nothing more than a class until we register it with an Angular injector. + + 在Angular 2中,服务其实只不过是一个类。 + 除非我们把它注册进一个Angular注入器,否则它没有任何特别之处。 // #enddocregion di-6 // #docregion di-configure-injector-1 :marked ### Configuring the injector + ### 配置注入器 We don't have to create an Angular injector. Angular creates an application-wide injector for us during the bootstrap process. + + + 我们并不需要自己创建一个Angular注入器。 + Angular在启动期间会自动为我们创建一个应用级注入器。 // #enddocregion di-configure-injector-1 -+makeExample('dependency-injection/ts/app/main.ts', 'bootstrap', 'app/main.ts (excerpt)')(format='.') ++makeExample('dependency-injection/ts/app/main.ts', 'bootstrap', 'app/main.ts (节选)')(format='.') // #docregion di-configure-injector-2 :marked We do have to configure the injector by registering the **providers** that create the services our application requires. We'll explain what [providers](#providers) are later in this chapter. Before we do, let's see an example of provider registration during bootstrapping: + + 我们必须先注册 **Provider** 来配置好注入器,这在创建应用所需的服务时会用到。 + 我们将在本章的稍后部分解释什么是[Provider](#providers)。 + 在此之前,我们先来看一个启动期间的注册Provider的例子。 // #enddocregion di-configure-injector-2 +makeExample('dependency-injection/ts/app/main.1.ts', 'bootstrap')(format='.') // #docregion di-configure-injector-3 :marked The injector now knows about our `HeroService`. An instance of our `HeroService` will be available for injection across our entire application. + + 注入器现在知道了我们的`HeroService`类。 + 这样,一个`HeroService`实例就可以在我们整个应用中都可用了。 Of course we can't help wondering about that comment telling us not to do it this way. It *will* work. It's just not a best practice. The bootstrap provider option is intended for configuring and overriding Angular's own preregistered services, such as its routing support. + + 当然,我们不禁要问,为什么注释中告诉我们不要这么做。 + 它 *能* 工作,但不是最佳实践。 + bootstrap函数的Provider选项是用来配置和改写Angular自身的预注册服务的,比如它的路由支持。 The preferred approach is to register application providers in application components. Because the `HeroService` is used within the *Heroes* feature area — and nowhere else — the ideal place to register it is in the top-level `HeroesComponent`. + + 首选的方式是在应用组件中注册应用级的Provider。 + 因为`HeroService`是用于 *英雄* 功能区的 —— 并且没别处用它 —— 所以注册它的理想地点就是`HeroesComponent`的顶层。 // #enddocregion di-configure-injector-3 // #docregion di-register-providers-1 :marked ### Registering providers in a component + ### 在组件中注册Provider Here's a revised `HeroesComponent` that registers the `HeroService`. + + 这里是注册了`HeroService`的修改版`HeroesComponent`。 // #enddocregion di-register-providers-1 +makeExample('dependency-injection/ts/app/heroes/heroes.component.1.ts',null,'app/heroes/heroes.component.ts') // #docregion di-register-providers-2 :marked Look closely at the `providers` part of the `@Component` metadata: + + 仔细看`@Component`元数据中的`providers`部分: // #enddocregion di-register-providers-2 +makeExample('dependency-injection/ts/app/heroes/heroes.component.1.ts','providers')(format='.') // #docregion di-register-providers-3 :marked An instance of the `HeroService` is now available for injection in this `HeroesComponent` and all of its child components. + + 现在,一个`HeroService`的实例就可以被注入到`HeroesComponent`及其全部子组件了。 The `HeroesComponent` itself doesn't happen to need the `HeroService`. But its child `HeroListComponent` does, so we head there next. + + `HeroesComponent`本身不需要`HeroService`,但它的子组件`HeroListComponent`需要,所以我们再往下看。 // #enddocregion di-register-providers-3 // #docregion di-prepare-for-injection-1 :marked ### Preparing the HeroListComponent for injection + ### 为注入准备`HeroListComponent` The `HeroListComponent` should get heroes from the injected `HeroService`. Per the dependency injection pattern, the component must ask for the service in its constructor, [as we explained earlier](#ctor-injection). It's a small change: + + `HeroListComponent`应该从注入进来的`HeroService`获取英雄数据。 + 遵照依赖注入模式的要求,组件必须在它的构造函数中请求这些服务,[就像我们以前解释过的那样](#ctor-injection)。 + // #enddocregion di-prepare-for-injection-1 +makeTabs( `dependency-injection/ts/app/heroes/hero-list.component.2.ts, diff --git a/public/docs/ts/latest/guide/forms.jade b/public/docs/ts/latest/guide/forms.jade index 0dce42bf90..027ef65770 100644 --- a/public/docs/ts/latest/guide/forms.jade +++ b/public/docs/ts/latest/guide/forms.jade @@ -158,7 +158,7 @@ include ../_quickstart_repo and one optional field (`alterEgo`). 最简单的模型就是一个“属性包儿”,用来存放关于应用中一个重要事物的那些事实。 - 这里我们使用三个必备字段(`id`、`name`、`power`),和一个可选字段(`alterEgo`,中文含义:闺蜜/好基友)。 + 这里我们使用三个必备字段(`id`、`name`、`power`),和一个可选字段(`alterEgo`,中文含义:第二人格)。 Create a new file in the app folder called `hero.ts` and give it the following class definition: @@ -459,7 +459,7 @@ figure.image-display and add a new binding at the top to the component's `diagnostic` property. Then we can confirm that two-way data binding works *for the entire Hero model*. - 让我们用类似的方式添加`[(ngModel)]`到 *好基友* 和 *超能力* 属性。 + 让我们用类似的方式添加`[(ngModel)]`到 *alterEgo* 和 *power* 属性。 我们将抛弃输入框的绑定消息,并在组件顶部的`diagnostic`属性上添加一个新的绑定。 然后我们能确认双向数据绑定 *在整个Hero模型上* 都是能工作的。 @@ -863,52 +863,83 @@ figure.image-display Upon reflection, we realize that Angular cannot distinguish between replacing the entire hero and clearing the `name` property programmatically. Angular makes no assumptions and leaves the control in its current, dirty state. + + 这反映出,在这种实现方式下,Angular没办法区分是替换了整个英雄数据还是用程序单独清除了`name`属性。 + Angular不能作出假设,因此只好让控件保留当前状态 —— 脏状态。 :marked We'll have to reset the form controls manually with a small trick. We add an `active` flag to the component, initialized to `true`. When we add a new hero, we toggle `active` false and then immediately back to true with a quick `setTimeout`. + + 我们不得不使用一个小花招来重置表单标志。 + 我们给组件添加一个`active`标记,把它初始化为`true`。当我们添加一个新的英雄时,它把`active`标记设置为`false`, + 然后通过一个快速的`setTimeout`函数迅速把它设置回`true`。 +makeExample('forms/ts/app/hero-form.component.ts', 'new-hero', - 'app/hero-form.component.ts (New Hero method - final)')(format=".") + 'app/hero-form.component.ts (新增英雄 - 最终版)')(format=".") :marked Then we bind the form element to this `active` flag. + + 然后,我们把form元素绑定到这个`active`标志上。 +makeExample('forms/ts/app/hero-form.component.html', 'form-active', - 'app/hero-form.component.html (Form tag)') + 'app/hero-form.component.html (Form标签)') :marked With `NgIf` bound to the `active` flag, clicking "New Hero" removes the form from the DOM and recreates it in a blink of an eye. The re-created form is in a pristine state. The error message is hidden. + + 在通过`NgIf`绑定到`active`标志之后,点击“新增英雄”将从DOM中移除这个表单,并且在一眨眼的功夫重建它。 + 重新创建的表单处于“全新”状态。错误信息被隐藏了。 .l-sub-section :marked This is a temporary workaround while we await a proper form reset feature. + + 这只是一个临时的变通方案,将来我们会有一个更合适的方案来重置表单。 :marked .l-main-section :marked ## Submit the form with **ngSubmit** + ## 通过 **ngSubmit** 来提交表单 The user should be able to submit this form after filling it in. The Submit button at the bottom of the form does nothing on its own but it will trigger a form submit because of its type (`type="submit"`). + + 在填写完之后,用户还应该能提交这个表单。 + 提交按钮位于表单的底部,它自己不会做任何事,但因为它特殊的type值(`type="submit"`),它会触发一次表单提交。 A "form submit" is useless at the moment. To make it useful, we'll update the `
` tag with another Angular directive, `NgSubmit`, and bind it to the `HeroFormComponent.submit()` method with an event binding + + 仅仅触发“表单提交”目前是没用的。 + 要让它有用,我们还要使用另一个Angular指令更新``标签 —— `NgSubmit`, + 并且通过事件绑定机制把它绑定到`HeroFormComponent.submit()`方法上。 +makeExample('forms/ts/app/hero-form.component.html', 'ngSubmit')(format=".") :marked We slipped in something extra there at the end! We defined a template local variable, **`#heroForm`**, and initialized it with the value, "ngForm". + + 最后,我们发现了一些额外的东西!我们定义了一个局部模板变量 **`#heroForm`** ,并且把它初始化为"ngForm"。 The variable `heroForm` is now a reference to the `NgForm` directive that governs the form as a whole. + + 这个`heroForm`变量现在引用的是`NgForm`指令,它代表的是作为整体的表单。 .l-sub-section :marked ### The NgForm directive + ### NgForm指令 What `NgForm` directive? We didn't add an [NgForm](../api/common/NgForm-directive.html) directive! + 什么是`NgForm`指令?我们没有添加过[NgForm](../api/common/NgForm-directive.html)指令! + Angular did. Angular creates and attaches an `NgForm` directive to the `` tag automatically. + + Angular替我们做了。Angular自动创建了`NgForm`指令,并且把它附加到``标签上。 The `NgForm` directive supplements the `form` element with additional features. It holds the controls we created for the elements with `ngControl` attributes @@ -916,27 +947,46 @@ figure.image-display It also has its own `valid` property which is true only *if every contained control* is valid. + `NgForm`指令使用额外的特性扩充了`form`元素。 + 它保存我们通过`ngControl`属性为各个元素创建的控件类,并且监听他们的属性变化,包括有效性。 + 它还有自己的`valid`属性,只有当 *每一个被包含的控件* 都有效时,它才有效。 + :marked Later in the template we bind the button's `disabled` property to the form's over-all validity via the `heroForm` variable. Here's that bit of markup: + + 模板中稍后的部分,通过`heroForm`变量,我们把按钮的`disabled`属性绑定到了表单的全员有效性。这里是那点儿HTML: +makeExample('forms/ts/app/hero-form.component.html', 'submit-button') :marked Re-run the application. The form opens in a valid state and the button is enabled. + + 重新运行应用。表单打开时,状态是有效的,按钮是可用的。 Now delete the *Name*. We violate the "name required" rule which is duely noted in our error message as before. And now the Submit button is also disabled. + + 现在,删除 *姓名* 。我们违反了“必填姓名”规则,它还是像以前那样显示了错误信息来提醒我们。同时,提交按钮也被禁用了。 Not impressed? Think about it for a moment. What would we have to do to wire the button's enable/disabled state to the form's validity without Angular's help? + + 没想明白?再想一会儿。如果没有Angular `NgForm`的帮助,我们该怎么让按钮的禁用/使能状态和表单的有效性关联起来呢? For us, it was as simple as + + 对于我们来说,它非常简单: 1. Define a template local variable on the (enhanced) form element + 1. 定义一个局部模板变量,放在(强化过的)form元素上 2. Reference that variable in a button some 50 lines away. + 2. 从50行之外的按钮上引用这个变量。 .l-main-section :marked ## Toggle two form regions (extra credit) + ## 切换两个表单区域(额外的荣誉) Submitting the form isn't terribly dramatic at the moment. + + 现在就提交表单还不够激动人心 .l-sub-section :marked An unsurprising observation for a demo. To be honest, @@ -945,19 +995,30 @@ figure.image-display binding skills. If you're not interested, you can skip to the chapter's conclusion and not miss a thing. + + 对演示来说,这是一个平淡的结尾。老实说,即使让它更出彩,也无法教给我们任何关于表单的新知识。 + 但这是一个锻炼我们新学到的绑定类技能的好机会。 + 如果你不感兴趣,可以跳过本章的下面这部分,而不会错失任何东西。 :marked Let's do something more strikingly visual. Let's hide the data entry area and display something else. + + 我们来做一些更明显的视觉效果吧。 + 隐藏掉数据输入框,并且显示一些别的东西。 Start by wrapping the form in a `
` and bind its `hidden` property to the `HeroFormComponent.submitted` property. + + 先把表单包裹进`
`中,并且把它的`hidden`属性绑定到`HeroFormComponent.submitted`属性上。 -+makeExample('forms/ts/app/hero-form.component.html', 'edit-div', 'app/hero-form.component.html (excerpt)')(format=".") ++makeExample('forms/ts/app/hero-form.component.html', 'edit-div', 'app/hero-form.component.html (节选)')(format=".") :marked The main form is visible from the start because the the `submitted` property is false until we submit the form, as this fragment from the `HeroFormComponent` reminds us: + + 主表单从一开始就是可见的,因为`submitted`属性是false,直到我们提交了这个表单,因为这个来自`HeroFormComponent`的片段提醒我们: +makeExample('forms/ts/app/hero-form.component.ts', 'submitted')(format=".") @@ -965,38 +1026,66 @@ figure.image-display When we click the Submit button, the `submitted` flag becomes true and the form disappears as planned. + 当我们点击提交按钮时,`submitted`标志会变成true,并且表单像预想中一样消失了。 + Now we need to show something else while the form is in the submitted state. Add the following block of HTML below the `
` wrapper we just wrote: -+makeExample('forms/ts/app/hero-form.component.html', 'submitted', 'app/hero-form.component.html (excerpt)') + + 现在,当表单处于已提交状态时,我们需要显示一些别的东西。 + 在我们刚刚写的`
`包装下方,添加下列HTML块儿: ++makeExample('forms/ts/app/hero-form.component.html', 'submitted', 'app/hero-form.component.html (节选)') :marked There's our hero again, displayed read-only with interpolation bindings. This slug of HTML only appears while the component is in the submitted state. + + 我们的英雄又来了,它通过插值表达式绑定显示为只读内容。 + 这一小段儿HTML只在组件处于已提交状态时才会显示。 We added an Edit button whose click event is bound to an expression that clears the `submitted` flag. + 我们添加了一个编辑按钮,它的click事件被绑定到了一个表达式,它会清除`submitted`标志。 + When we click it, this block disappears and the editable form reappears. + + 当我们点它时,这个只读块消失了,可编辑的表单重新出现了。 That's as much drama as we can muster for now. + + 现在,它比我们那个恰好够用的版本好看多了。 .l-main-section :marked ## Conclusion + ## 结论 The Angular 2 form discussed in this chapter takes advantage of the following framework features to provide support for data modification, validation and more: + + 从本章对Angular 2表单的讨论中得到的用来支持数据修改、验证等的框架高级特性如下: - An Angular HTML form template. + - Angular HTML表单模板。 - A form component class with a `Component` decorator. + - 带有`Component`装饰器的组件类。 - The `ngSubmit` directive for handling the form submission. + - 用来处理表单提交的`ngSubmit`指令。 - Template local variables such as `#heroForm`, `#name`, `#alter-ego` and `#power`. + - 局部模板变量,如`#heroForm`、`#name`、`#alter-ego`和`power`。 - The `[(ngModel)]` syntax for two-way data binding. + - 用于双向数据绑定的`[(ngModel)]`语法 - The `ngControlName` directive for validation and form element change tracking. + - 用于验证和表单元素变化跟踪的`ngControlName`指令 - The local variable’s `valid` property on input controls to check if a control is valid and show/hide error messages. + - 代表输入控件的局部变量上的`valid`属性,用于检查控件是否有效、是否显示/隐藏错误信息。 - Controlling the submit button's enabled state by binding to `NgForm` validity. + - 通过绑定到`NgForm`的有效性状态,控制提交按钮的禁用状态。 - Custom CSS classes that provide visual feedback to users about invalid controls. + - 对无效控件,定制CSS类来给用户提供视觉反馈。 Our final project folder structure should look like this: + + 我们最终的项目目录结构看起来是这样: .filetree .file angular2-forms .children @@ -1015,6 +1104,8 @@ figure.image-display .file typings.json :marked Here’s the final version of the source: + + 这里是源码的最终版本: +makeTabs( `forms/ts/app/hero-form.component.ts,