@title
路由

@intro
添加 Angular 组件路由，并且学习在视图之间导航

@description



There are new requirements for the Tour of Heroes app:

我们收到了《英雄指南》的一些新需求：

* Add a *Dashboard* view.

  添加一个*仪表盘*视图。

* Add the ability to navigate between the *Heroes* and *Dashboard* views.

  在*英雄列表*和*仪表盘*视图之间导航。

* When users click a hero name in either view, navigate to a detail view of the selected hero.

  无论在哪个视图中点击一个英雄，都会导航到该英雄的详情页。

* When users click a *deep link* in an email, open the detail view for a particular hero.

  在邮件中点击一个*深链接*，会直接打开一个特定英雄的详情视图。

When you’re done, users will be able to navigate the app like this:

完成时，用户就能像这样在应用中导航：


<figure class='image-display'>
  <img src='assets/images/devguide/toh/nav-diagram.png' alt="查看导航"></img>
</figure>



To satisfy these requirements, you'll add Angular’s router to the app.

我们将把 Angular *路由器*加入应用中，以满足这些需求。
(译注：硬件领域中的路由器是用来帮你找到另一台网络设备的，而这里的路由器用于帮你找到一个组件)


<div class="l-sub-section">



For more information about the router, read the [Routing and Navigation](guide/router) page.

更多信息，见[路由和导航](guide/router)。


</div>



When you're done with this page, the app should look like this <live-example></live-example>.

完成本章之后，应用会变成这样：<live-example></live-example>。



## Where you left off

## 延续上一步教程

Before continuing with the Tour of Heroes, verify that you have the following structure.

在继续《英雄指南》之前，我们先验证一下目录结构：



<div class='filetree'>

  <div class='file'>
    angular-tour-of-heroes
  </div>

  <div class='children'>

    <div class='file'>
      src
    </div>

    <div class='children'>

      <div class='file'>
        app
      </div>

      <div class='children'>

        <div class='file'>
          app.component.ts
        </div>

        <div class='file'>
          app.module.ts
        </div>

        <div class='file'>
          hero.service.ts
        </div>

        <div class='file'>
          hero.ts
        </div>

        <div class='file'>
          hero-detail.component.ts
        </div>

        <div class='file'>
          mock-heroes.ts
        </div>

      </div>

      <div class='file'>
        main.ts
      </div>

      <div class='file'>
        index.html
      </div>

      <div class='file'>
        styles.css
      </div>

      <div class='file'>
        systemjs.config.js
      </div>

      <div class='file'>
        tsconfig.json
      </div>

    </div>

    <div class='file'>
      node_modules ...
    </div>

    <div class='file'>
      package.json
    </div>

  </div>

</div>



## Keep the app transpiling and running

## 让应用代码保持转译和运行

Enter the following command in the terminal window:

打开终端/控制台窗口，运行如下命令：


<code-example language="sh" class="code-shell">
  npm start

</code-example>



This command runs the TypeScript compiler in "watch mode", recompiling automatically when the code changes.
The command simultaneously launches the app in a browser and refreshes the browser when the code changes.

这个命令会在“监听”模式下运行TypeScript编译器，当代码变化时，它会自动重新编译。
  同时，该命令还会在浏览器中启动该应用，并且当代码变化时刷新浏览器。


You can keep building the Tour of Heroes without pausing to recompile or refresh the browser.

在后续构建《英雄指南》过程中，应用能持续运行，而不用中断服务来编译或刷新浏览器。

## Action plan

## 行动计划

Here's the plan:

下面是我们的计划：

* Turn `AppComponent` into an application shell that only handles navigation.

  把`AppComponent`变成应用程序的“壳”，它只处理导航
  
* Relocate the *Heroes* concerns within the current `AppComponent` to a separate `HeroesComponent`.

  把现在由`AppComponent`关注的*英雄们*移到一个独立的`HeroesComponent`中
  
* Add routing.

  添加路由
  
* Create a new `DashboardComponent`.

  创建一个新的`DashboardComponent`组件
  
* Tie the *Dashboard* into the navigation structure.

  把*仪表盘*加入导航结构中


<div class="l-sub-section">



*Routing* is another name for *navigation*. The router is the mechanism for navigating from view to view.

*路由*是导航的另一个名字。*路由器*就是从一个视图导航到另一个视图的机制。


</div>




## Splitting the *AppComponent*

## 拆分 *AppComponent*

The current app loads `AppComponent` and immediately displays the list of heroes.

现在的应用会加载`AppComponent`组件，并且立刻显示出英雄列表。

The revised app should present a shell with a choice of views (*Dashboard* and *Heroes*)
and then default to one of them.

我们修改后的应用将提供一个壳，它会选择*仪表盘*和*英雄列表*视图之一，然后默认显示它。

The `AppComponent` should only handle navigation, so you'll
move the display of *Heroes* out of `AppComponent` and into its own `HeroesComponent`.

`AppComponent`组件应该只处理导航。
我们来把*英雄列表*的显示职责，从`AppComponent`移到`HeroesComponent`组件中。

### *HeroesComponent*

`AppComponent` is already dedicated to *Heroes*.
Instead of moving the code out of `AppComponent`, rename it to `HeroesComponent`
and create a separate `AppComponent` shell.

`AppComponent`的职责已经被移交给`HeroesComponent`了。
  与其把`AppComponent`中所有的东西都搬过去，不如索性把它改名为`HeroesComponent`，然后单独创建一个新的`AppComponent`壳。

Do the following:

步骤如下：

* Rename the <code>app.component.ts</code> file to <code>heroes.component.ts</code>.

  把<code>app.component.ts</code>文件改名为<code>heroes.component.ts</code>。

* Rename the `AppComponent` class as `HeroesComponent` (rename locally, _only_ in this file).

  把`AppComponent`类改名为`HeroesComponent`（注意，*只*在这一个文件中改名）。
  
* Rename the selector `my-app` as `my-heroes`.

  把`my-app`选择器改名为`my-heroes`。


<code-example path="toh-5/src/app/heroes.component.ts" region="renaming" title="src/app/heroes.component.ts (showing renamings only)">

</code-example>



### Create *AppComponent*

### 创建 *AppComponent*

The new `AppComponent` is the application shell.
It will have some navigation links at the top and a display area below.

新的`AppComponent`将成为应用的“壳”。
  它将在顶部放一些导航链接，并且把我们要导航到的页面放在下面的显示区中。

Perform these steps:

执行下列步骤：

* add the supporting `import` statements.

  添加支持性的`import`语句。

* Create the file <code>src/app/app.component.ts</code>.

  创建一个名叫<span ngio-ex>src/app/app.component.ts</span>的新文件。
  
* Define an exported `AppComponent` class.

  定义一个导出的 `AppComponent`类。

* Add an `@Component` decorator above the class with a `my-app` selector.

  在类的上方添加`@Component`元数据装饰器，装饰器带有`my-app`选择器。
  
* Move the following from `HeroesComponent` to `AppComponent`:

  将下面的项目从`HeroesComponent`移到`AppComponent`：    
* `title` class property.

  `title`类属性    

* `@Component` template `<h1>` element, which contains a binding to  `title`.

  `@Component`模板中的`<h1>`标签，它包含了对`title`属性的绑定。  
  
* Add a `<my-heroes>` element to the app template just below the heading so you still see the heroes.

  在模板的标题下面添加`<my-heroes>`标签，以便我们仍能看到英雄列表。  
  
* Add `HeroesComponent` to the `declarations` array of `AppModule` so Angular recognizes the `<my-heroes>` tags.

  添加`HeroesComponent`组件到根模块的`declarations`数组中，以便 Angular 能认识`<my-heroes>`标签。  
  
* Add `HeroService` to the  `providers` array of `AppModule` because you'll need it in every other view.

  添加`HeroService`到`AppModule`的`providers`数组中，因为我们的每一个视图都需要它。  
  
* Remove `HeroService` from the `HeroesComponent` `providers` array since it was promoted.

  从`HerosComponent`的`providers`数组中移除`HeroService`，因为它被提到模块了。
  
* Add the supporting `import` statements for `AppComponent`.

  为`AppComponent`添加一些`import`语句。

The first draft looks like this:

我们的第一个草稿版就像这样：


<code-tabs>

  <code-pane title="src/app/app.component.ts (v1)" path="toh-5/src/app/app.component.1.ts">

  </code-pane>

  <code-pane title="src/app/app.module.ts (v1)" path="toh-5/src/app/app.module.1.ts">

  </code-pane>

</code-tabs>





<div class="callout is-critical">



<header>
  Remove <i>HeroService</i> from the <i>HeroesComponent</i> providers
</header>



<header>
  从<i>HeroesComponent</i>的<code>providers</code>中移除<i>HeroService</i>
</header>



Go back to the `HeroesComponent` and **remove the `HeroService`** from its `providers` array.
We are *promoting* this service from the `HeroesComponent` to the root `NgModule`.
We ***do not want two copies*** of this service at two different levels of our app.

回到`HeroesComponent`，并从`providers`数组中**移除`HeroService`**。
把它从`HeroesComponent`*提升*到根`NgModule`中。
我们不希望在应用的两个不同层次上存在它的***两个副本***。


</div>



The app still runs and displays heroes.

应用仍然在运行，并显示着英雄列表。


## Add routing

## 添加路由

Instead of displaying automatically, heroes should display after users click a button.
In other words, users should be able to navigate to the list of heroes.

我们希望在用户点击按钮之后才显示英雄列表，而不是自动显示。
  换句话说，我们希望用户能“导航”到英雄列表。

Use the Angular router to enable navigation.

我们要使用 Angular *路由器*进行导航。


The Angular router is an external, optional Angular NgModule called `RouterModule`.
The router is a combination of multiple provided services (`RouterModule`),
multiple directives (`RouterOutlet, RouterLink, RouterLinkActive`),
and a configuration (`Routes`). You'll configure the routes first.

Angular 路由器是一个可选的外部 Angular NgModule，名叫`RouterModule`。
路由器包含了多种服务(`RouterModule`)、多种指令(`RouterOutlet、RouterLink、RouterLinkActive`)、
和一套配置(`Routes`)。我们将先配置路由。


### *&lt;base href>*

Open `index.html` and ensure there is a `<base href="...">` element
(or a script that dynamically sets this element)
at the top of the `<head>` section.

打开`index.html`，确保它的`<head>`区顶部有一个`<base href="...">`元素（或动态生成该元素的脚本）。


<code-example path="toh-5/src/index.html" region="base-href" title="src/index.html (base-href)">

</code-example>



<div class="callout is-important">



<header>
  base href is essential
</header>



<header>
  基地址（base href）是必须的
</header>



For more information, see the [Set the base href](guide/router#!)
section of the [Routing and Navigation](guide/router) page.

要了解更多信息，请参见[路由与导航](guide/router)章的[设置基地址（base href）](guide/router#!)部分。



</div>



{@a configure-routes}


### Configure routes

### 配置路由

Create a configuration file for the app routes.

本应用还没有路由。我们来为应用的路由新建一个配置。


*Routes* tell the router which views to display when a user clicks a link or
pastes a URL into the browser address bar.

*路由*告诉路由器，当用户点击链接或者把 URL 粘贴到浏览器地址栏时，应该显示哪个视图。

Define the first route as a route to the heroes component.

我们的第一个路由是指向英雄列表组件的。


<code-example path="toh-5/src/app/app.module.2.ts" region="heroes" title="src/app/app.module.ts (heroes route)">

</code-example>



The `Routes` are an array of *route definitions*.

这个`Routes`是一个*路由定义*的数组。
此时，我们只有一个路由定义，但别急，后面还会添加更多。

This route definition has the following parts:

*路由定义*包括以下部分：

* *Path*: The router matches this route's path to the URL in the browser address bar (`heroes`).

  **Path**: 路由器会用它来匹配浏览器地址栏中的地址，如`heroes`。
  
* *Component*: The component that the router should create when navigating to this route (`HeroesComponent`).

  *Component*: 导航到此路由时，路由器需要创建的组件（`HeroesComponent`）。


<div class="l-sub-section">



Read more about defining routes with `Routes` in the [Routing & Navigation](guide/router) page.

关于`Routes`定义的更多信息，见[路由与导航](guide/router)一章。


</div>



### Make the router available

### 让路由器可用

Import the `RouterModule` and add it to the `AppModule` imports array.

导入`RouterModule`并添加到`AppModule`的`imports`数组中。


<code-example path="toh-5/src/app/app.module.2.ts" title="src/app/app.module.ts (app routing)">

</code-example>



<div class="l-sub-section">



The `forRoot()` method is called because a configured router is provided at the app's root.
The `forRoot()` method supplies the Router service providers and directives needed for routing, and
performs the initial navigation based on the current browser URL.

这里使用了`forRoot()`方法，因为我们是在应用*根部*提供配置好的路由器。
`forRoot()`方法提供了路由需要的路由服务提供商和指令，并基于当前浏览器 URL 初始化导航。


</div>



### Router outlet

### 路由出口(Outlet)

If you paste the path, `/heroes`, into the browser address bar at the end of the URL,
the router should match it to the `heroes` route and display the `HeroesComponent`.
However, you have to tell the router where to display the component.
To do this, you can add a `<router-outlet>` element at the end of the template.
`RouterOutlet` is one of the directives provided by the `RouterModule`.
The router displays each component immediately below the `<router-outlet>` as users navigate through the app.

如果我们把路径`/heroes`粘贴到浏览器的地址栏，路由器会匹配到`'Heroes'`路由，并显示`HeroesComponent`组件。
我们必须***告诉路由器它位置***，所以我们把`<router-outlet>`标签添加到模板的底部。
  `RouterOutlet`是由`RouterModule`提供的指令之一。
  当我们在应用中导航时，路由器就把激活的组件显示在`<router-outlet>`里面。

### Router links

### 路由器链接

Users shouldn't have to paste a route URL into the address bar.
Instead, add an anchor tag to the template that, when clicked, triggers navigation to the `HeroesComponent`.

我们当然不会真让用户往地址栏中粘贴路由的 URL，
而应该在模板中的什么地方添加一个锚标签。点击时，就会导航到`HeroesComponent`组件。

The revised template looks like this:

修改过的模板是这样的：


<code-example path="toh-5/src/app/app.component.1.ts" region="template-v2" title="src/app/app.component.ts (template-v2)">

</code-example>



Note the `routerLink` binding in the anchor tag.
The `RouterLink` directive (another of the `RouterModule` directives) is bound to a string
that tells the router where to navigate when the user clicks the link.

注意，锚标签中的`[routerLink]`绑定。
我们把`RouterLink`指令（`ROUTER_DIRECTIVES`中的另一个指令）绑定到一个字符串。
它将告诉路由器，当用户点击这个链接时，应该导航到哪里。

Since the link is not dynamic,  a routing instructionis defined with a one-time binding to the route path.
Looking back at the route configuration, you can confirm that `'/heroes'` is the path of the route to the `HeroesComponent`.

由于这个链接不是动态的，我们只要用**一次性绑定**的方式绑定到路由的**路径 (path) **就行了。
回来看路由配置表，我们清楚的看到，这个路径 —— `'/heroes'`就是指向`HeroesComponent`的那个路由的路径。


<div class="l-sub-section">



Read more about dynamic router links and the link parameters array
in the [Appendix: Link Parameters Array](guide/router#link-parameters-array) section of the
[Routing & Navigation](guide/router) page.

关于动态路由器链接和*链接参数数组更多信息，见[路由与导航](guide/router)中的[附录：链接参数数组](guide/router#link-parameters-array)部分。


</div>



Refresh the browser. The browser displays the app title and heroes link, but not the heroes list.

刷新浏览器。我们只看到了应用标题和英雄链接。英雄列表到哪里去了？


<div class="l-sub-section">



The browser's address bar shows `/`.
The route path to `HeroesComponent` is `/heroes`, not `/`.
Soon you'll add a route that matches the path `/`.

浏览器的地址栏显示的是`/`。而到`HeroesComponent`的路由中的路径是`/heroes`，不是`/`。
我们没有任何路由能匹配当前的路径`/`，所以，自然没啥可显示的。
接下来，我们就修复这个问题。


</div>



Click the *Heroes* navigation link. The address bar updates to `/heroes`
and the list of heroes displays.

我们点击“Heroes（英雄列表）”导航链接，浏览器地址栏更新为`/heroes`，并且看到了英雄列表。我们终于导航过去了！

`AppComponent` now looks like this:

现在，`AppComponent`是这样的：


<code-example path="toh-5/src/app/app.component.1.ts" region="v2" title="src/app/app.component.ts (v2)">

</code-example>



The  *AppComponent* is now attached to a router and displays routed views.
For this reason, and to distinguish it from other kinds of components,
this component type is called a *router component*.

*AppComponent*现在加上了路由器，并能显示路由到的视图了。
因此，为了把它从其它种类的组件中区分出来，我们称这类组件为*路由器组件*。


## Add a dashboard

## 添加一个*仪表盘*

Routing only makes sense when multiple views exist.
To add another view, create a placeholder `DashboardComponent`, which users can navigate to and from.

当我们有多个视图的时候，路由才有意义。所以我们需要另一个视图。先创建一个`DashboardComponent`的占位符，让用户可以导航到它或从它导航出来。


<code-example path="toh-5/src/app/dashboard.component.1.ts" title="src/app/dashboard.component.ts (v1)">

</code-example>



You'll make this component more useful later.

我们先不实现它，稍后，我们再回来，给这个组件一些实际用途。

### Configure the dashboard route

### 配置仪表盘路由

To teach `app.module.ts` to navigate to the dashboard,
import the dashboard component and
add the following route definition to the `Routes` array of definitions.

要让`app.module.ts`能导航到仪表盘，就要先导入仪表盘组件，然后把下列路由定义添加到`Routes`数组中。


<code-example path="toh-5/src/app/app.module.3.ts" region="dashboard" title="src/app/app.module.ts (Dashboard route)">

</code-example>



Also import and add `DashboardComponent` to the `AppModule`'s `declarations`.

然后还得把`DashboardComponent`添加到`AppModule`的`declarations`数组中。


<code-example path="toh-5/src/app/app.module.ts" region="dashboard" title="src/app/app.module.ts(dashboard)">

</code-example>



### Add a redirect route

### 添加重定向路由

Currently, the browser launches with `/` in the address bar.
When the app starts, it should show the dashboard and
display a `/dashboard` URL in the browser address bar.

浏览器启动时地址栏中的地址是`/`。
当应用启动时，它应该显示仪表盘，并且在浏览器的地址栏显示URL：`/dashboard`


To make this happen, use a redirect route. Add the following
to the array of route definitions:

我们可以使用重定向路由来实现它。把下面的内容添加到路由定义数组中：


<code-example path="toh-5/src/app/app.module.3.ts" region="redirect" title="src/app/app.module.ts (redirect)">

</code-example>



<div class="l-sub-section">



Read more about *redirects* in the [Redirecting routes](guide/router#!) section
of the [Routing & Navigation](guide/router) page.

关于*重定向*的更多信息，见[路由](guide/router#redirect)。


</div>



### Add navigation to the template

### 添加导航到模版中

Add a dashboard navigation link to the template, just above the *Heroes* link.

在模板上添加一个到仪表盘的导航链接，就放在*Heroes（英雄列表）*链接的上方。


<code-example path="toh-5/src/app/app.component.1.ts" region="template-v3" title="src/app/app.component.ts (template-v3)">

</code-example>



<div class="l-sub-section">



The `<nav>` tags don't do anything yet, but they'll be useful later when you style the links.

我们在`<nav>`标签中放了两个链接。
它们现在还没有作用，但稍后，当我们对这些链接添加样式时，会显得比较方便。


</div>



In your browser, go to the application root (`/`) and reload.
The app displays the dashboard and you can navigate between the dashboard and the heroes.

刷新浏览器。应用显示出了仪表盘，并可以在仪表盘和英雄列表之间导航了。

## Add heroes to the dashboard

## 把英雄添加到仪表盘

To make the dashboard more interesting, you'll display the top four heroes at a glance.

我们想让仪表盘更有趣，比如：让用户一眼就能看到四个顶级英雄。

Replace the `template` metadata with a `templateUrl` property that points to a new
template file.

把元数据中的`template`属性替换为`templateUrl`属性，它将指向一个新的模板文件。


<code-example path="toh-5/src/app/dashboard.component.ts" region="metadata" title="src/app/dashboard.component.ts (metadata)">

</code-example>



Create that file with this content:

使用下列内容创建文件：


<code-example path="toh-5/src/app/dashboard.component.1.html" title="src/app/dashboard.component.html">

</code-example>



`*ngFor` is used again to iterate over a list of heroes and display their names.
The extra `<div>` elements will help with styling later.

我们再次使用`*ngFor`来在英雄列表上迭代，并显示它们的名字。
还添加了一个额外的`<div>`元素，来帮助稍后的美化工作。

### Sharing the *HeroService*

### 共享 *HeroService*

To populate the component's `heroes` array, you can re-use the `HeroService`.

要想管理该组件的`heroes`数组，我们可以复用`HeroService`。

Earlier, you removed the `HeroService` from the `providers` array of `HeroesComponent`
and added it to the `providers` array of `AppModule`.
That move created a singleton `HeroService` instance, available to all components of the app.
Angular injects `HeroService` and you can use it in the `DashboardComponent`.

在前面的章节中，我们从`HeroesComponent`的`providers`数组中移除了`HeroService`服务，
  并把它添加到`AppModule`的`providers`数组中。
这个改动创建了一个`HeroService`的单例对象，应用中的*所有*组件都可以使用它。
Angular 会把`HeroService`注入到`DashboardComponent`，我们就能在`DashboardComponent`中使用它了。

### Get heroes

### 获取英雄数据

In <code>dashboard.component.ts</code>, add the following `import` statements.

打开<code>dashboard.component.ts</code>文件，并添加下列`import`语句。


<code-example path="toh-5/src/app/dashboard.component.ts" region="imports" title="src/app/dashboard.component.ts (imports)">

</code-example>



We need `OnInit` interface because we'll initialize the heroes in the `ngOnInit` method as we've done before.
We need the `Hero` and `HeroService` symbols in order to reference those types.

我们需要实现`OnInit`接口，因为我们将在`ngOnInit`方法中初始化英雄数组 —— 就像上次一样。
我们需要导入`Hero`类和`HeroService`类来引用它们的数据类型。

Now create the `DashboardComponent` class like this:

我们现在就实现`DashboardComponent`类，像这样：


<code-example path="toh-5/src/app/dashboard.component.ts" region="class" title="src/app/dashboard.component.ts (class)">

</code-example>



This kind of logic is also used in the `HeroesComponent`:

我们在之前的`HeroesComponent`中也看到过类似的逻辑：

* Define a `heroes` array property.

  创建一个`heroes`数组属性。

* Inject the `HeroService` in the constructor and hold it in a private `heroService` field.

  在构造函数中注入`HeroService`，并且把它保存在一个私有的`heroService`字段中。

* Call the service to get heroes inside the Angular `ngOnInit()` lifecycle hook.

  在 Angular 的`ngOnInit`生命周期钩子里面调用服务来获得英雄数据。

In this dashboard you specify four heroes (2nd, 3rd, 4th, and 5th) with the `Array.slice` method.

在仪表盘中我们用`Array.slice`方法提取了四个英雄（第2、3、4、5个）。

Refresh the browser to see four hero names in the new dashboard.

刷新浏览器，在这个新的仪表盘中就看到了四个英雄。



## Navigating to hero details

## 导航到英雄详情

While the details of a selected hero displays at the bottom of the `HeroesComponent`,
users should be able to navigate to the `HeroDetailComponent` in the following additional ways:

虽然我们在`HeroesComponent`组件的底部显示了所选英雄的详情，
  但用户还没法*导航*到`HeroDetailComponent`组件。我们可以用下列方式导航到`HeroDetailComponent`：

* From the dashboard to a selected hero.

  从*Dashboard（仪表盘）*导航到一个选定的英雄。
  
* From the heroes list to a selected hero.

  从*Heroes（英雄列表）*导航到一个选定的英雄。
  
* From a "deep link" URL pasted into the browser address bar.

  把一个指向该英雄的“深链接” URL 粘贴到浏览器的地址栏。

### Routing to a hero detail

### 路由到一个英雄详情

You can add a route to the `HeroDetailComponent` in `app.module.ts`, where the other routes are configured.

我们将在`app.module.ts`中添加一个到`HeroDetailComponent`的路由，也就是配置其它路由的地方。

The new route is unusual in that you must tell the `HeroDetailComponent` which hero to show.
You didn't have to tell the `HeroesComponent` or the `DashboardComponent` anything.

这个新路由的不寻常之处在于，我们必须告诉`HeroDetailComponent`*该显示哪个英雄*。
  之前，我们不需要告诉`HeroesComponent`组件和`DashboardComponent`组件任何东西。

Currently, the parent `HeroesComponent` sets the component's `hero` property to a
hero object with a binding like this:

现在，父组件`HeroesComponent`通过数据绑定来把一个英雄对象设置为组件的`hero`属性。就像这样：


<code-example language="html">
  &lt;hero-detail [hero]="selectedHero">&lt;/hero-detail>

</code-example>



But this binding won't work in any of the routing scenarios.

显然，在我们的任何一个路由场景中它都无法工作。
最后一种场景肯定不行，我们无法将一个完整的 hero 对象嵌入到 URL 中！不过我们本来也不想这样。

### Parameterized route

### 参数化路由

You can add the hero's `id` to the URL. When routing to the hero whose `id` is 11,
you could expect to see a URL such as this:

我们*可以*把英雄的`id`添加到 URL 中。当导航到一个`id`为 11 的英雄时，我们期望的 URL 是这样的：


<code-example format="nocode">
  /detail/11

</code-example>



The `/detail/` part of the URL is constant. The trailing numeric `id` changes from hero to hero.
You need to represent the variable part of the route with a *parameter* (or *token*) that stands for the hero's `id`.

URL中的`/detail/`部分是固定不变的，但结尾的数字`id`部分会随着英雄的不同而变化。
我们要把路由中可变的那部分表示成一个*参数 (parameter) *或*令牌 (token) *，代表英雄的`id`。

### Configure a route with a parameter

### 配置带参数的路由

Use the following *route definition*.

我们将使用下列*路由定义*。


<code-example path="toh-5/src/app/app.module.3.ts" region="hero-detail" title="src/app/app.module.ts (hero detail)">

</code-example>



The colon (:) in the path indicates that `:id` is a placeholder for a specific hero `id`
when navigating to the `HeroDetailComponent`.

路径中的冒号 (:) 表示`:id`是一个占位符，当导航到这个`HeroDetailComponent`组件时，它将被填入一个特定英雄的`id`。


<div class="l-sub-section">



Be sure to import the hero detail component before creating this route.

别忘了在创建这个路由前导入英雄详情组件。


</div>



You're finished with the app routes.

我们已经完成了本应用的路由的配置。

You didn't add a `'Hero Detail'` link to the template because users
don't click a navigation *link* to view a particular hero;
they click a *hero name*, whether the name displays on the dashboard or in the heroes list.

我们没有往模板中添加一个`'英雄详情'`，这是因为用户不会直接点击导航栏中的链接去查看一个特定的英雄。
  它们只会通过在英雄列表或者仪表盘中点击来显示一个英雄。

You don't need to add the hero clicks until the `HeroDetailComponent`
is revised and ready to be navigated to.

要想支持“点击英雄”，就得先对`HeroDetailComponent`进行修改，好让我们能导航到它。



## Revise the *HeroDetailComponent*

## 修改*HeroDetailComponent*

Here's what the `HeroDetailComponent` looks like now:

在重写`HeroDetailComponent`之前，我们先看看它现在的样子：


<code-example path="toh-4/src/app/hero-detail.component.ts" title="src/app/hero-detail.component.ts (current)">

</code-example>



The template won't change. Hero names will display the same way.
The major changes are driven by how you get hero names.

模板不用修改，我们会用原来的方式显示英雄。导致这次大修的原因是如何获得这个英雄的数据。


You'll no longer receive the hero in a parent component property binding.
The new `HeroDetailComponent` should take the `id` parameter from the `params` Observable
in the `ActivatedRoute` service and use the `HeroService` to fetch the hero with that `id`.

我们不会再从父组件的属性绑定中接收英雄数据。
新的`HeroDetailComponent`应该从`ActivatedRoute`服务的可观察对象`params`中取得`id`参数，
并通过`HeroService`服务获取具有这个指定`id`的英雄数据。


Add the following imports:

先添加下列导入语句：


<code-example path="toh-5/src/app/hero-detail.component.1.ts" region="added-imports" title="src/app/hero-detail.component.ts">

</code-example>



Inject the `ActivatedRoute`, `HeroService`, and `Location` services
into the constructor, saving their values in private fields:

然后注入`ActivatedRoute`和`HeroService`服务到构造函数中，将它们的值保存到私有变量中：


<code-example path="toh-5/src/app/hero-detail.component.ts" region="ctor" title="src/app/hero-detail.component.ts (constructor)">

</code-example>



<code-example path="toh-5/src/app/hero-detail.component.ts" region="rxjs-import" title="src/app/hero-detail.component.ts (switchMap import)">

</code-example>



Tell the class to implement the `OnInit` interface.

我们告诉这个类，我们要实现`OnInit`接口。


<code-example path="toh-5/src/app/hero-detail.component.ts" region="implement" title="src/app/hero-detail.component.ts">

</code-example>



Inside the `ngOnInit()` lifecycle hook, use the `params` Observable to
extract the `id` parameter value from the `ActivatedRoute` service
and use the `HeroService` to fetch the hero with that `id`.

在`ngOnInit()`生命周期钩子中，我们从`ActivatedRoute`服务的可观察对象`params`中提取`id`参数，
并且使用`HeroService`来获取具有这个`id`的英雄数据。。


<code-example path="toh-5/src/app/hero-detail.component.ts" region="ngOnInit" title="src/app/hero-detail.component.ts">

</code-example>



The `switchMap` operator maps the `id` in the Observable route parameters
to a new `Observable`, the result of the `HeroService.getHero()` method.

注意`switchMap`运算符如何将可观察的路由参数中的 `id` 映射到一个新的`Observable`，
即`HeroService.getHero()`方法的结果。
  
If a user re-navigates to this component while a `getHero` request is still processing,
  `switchMap` cancels the old request and then calls `HeroService.getHero()` again.

如果用户在 `getHero` 请求执行的过程中再次导航这个组件，`switchMap` 再次调用`HeroService.getHero()`之前，
    会取消之前的请求。


The hero `id` is a number. Route parameters are always strings.
So the route parameter value is converted to a number with the JavaScript (+) operator.

英雄的`id`是数字，而路由参数的值*总是字符串*。
  所以我们需要通过 JavaScript 的 (+) 操作符把路由参数的值转成数字。


<div class="l-sub-section">



### Do you need to unsubscribe?

### 我需要取消订阅吗？

As described in the [ActivatedRoute: the one-stop-shop for route information](guide/router#activated-route)
section of the [Routing & Navigation](guide/router) page,
the `Router` manages the observables it provides and localizes
the subscriptions. The subscriptions are cleaned up when the component is destroyed, protecting against
memory leaks, so you don't need to unsubscribe from the route `params` `Observable`.

正如以前在[路由与导航](guide/router)章的[ActivatedRoute：一站式获取路由信息](guide/router#activated-route)部分讲过的，`Router`管理它提供的[可观察对象](guide/router#activated-route)，并使订阅局部化。当组件被销毁时，会清除
订阅，防止内存泄漏，所以我们不需要从路由参数`Observable`_取消订阅_。


</div>



### Add *HeroService.getHero()*

### 添加 *HeroService.getHero()*

In the previous code snippet, `HeroService` doesn't have a `getHero()` method. To fix this issue,
open `HeroService` and add a `getHero()` method that filters the heroes list from `getHeroes()` by `id`.

在前面的代码片段中`HeroService`没有`getHero()`方法。要解决这个问题，请打开`HeroService`并添加一个`getHero()`方法，它会根据`id`从`getHeroes()`中过滤英雄列表。


<code-example path="toh-5/src/app/hero.service.ts" region="getHero" title="src/app/hero.service.ts (getHero)">

</code-example>



### Find the way back

### 回到原路

Users have several ways to navigate *to* the `HeroDetailComponent`.

用户有多种方式导航到`HeroDetailComponent`。

To navigate somewhere else, users can click one of the two links in the `AppComponent` or click the browser's back button.
Now add a third option, a `goBack()` method that navigates backward one step in the browser's history stack
using the `Location` service you injected previously.

要导航到别处，用户可以点击`AppComponent`中的两个链接之一，也可以点击浏览器的后退按钮。
我们来添加第三个选项：一个`goBack()`方法，它使用之前注入的`Location`服务，
  利用浏览器的历史堆栈，导航到上一步。


<code-example path="toh-5/src/app/hero-detail.component.ts" region="goBack" title="src/app/hero-detail.component.ts (goBack)">

</code-example>



<div class="l-sub-section">



Going back too far could take users out of the app.
In a real app, you can prevent this issue with the <em>CanDeactivate</em> guard.
Read more on the [CanDeactivate](api/router/index/CanDeactivate-interface) page.

回退太多步会跑出我们的应用。
在真实的应用中，我们需要使用<em>CanDeactivate</em>守卫对此进行防范。
要了解更多，参见[CanDeactivate](api/router/index/CanDeactivate-interface)。


</div>



You'll wire this method with an event binding to a *Back* button that you'll add to the component template.

然后，我们通过一个事件绑定把此方法绑定到模板底部的 *Back（后退）*按钮上。


<code-example path="toh-5/src/app/hero-detail.component.html" region="back-button">

</code-example>



Migrate the template to its own file
called <code>hero-detail.component.html</code>:

修改模板，添加这个按钮以提醒我们还要做更多的改进，
并把模板移到独立的<span ngio-ex>hero-detail.component.html</span>文件中去。


<code-example path="toh-5/src/app/hero-detail.component.html" title="src/app/hero-detail.component.html">

</code-example>



Update the component metadata with a `templateUrl` pointing to the template file that you just created.

然后修改组件元数据的`templateUrl`属性，让它指向我们刚刚创建的模板文件。


<code-example path="toh-5/src/app/hero-detail.component.ts" region="metadata" title="src/app/hero-detail.component.ts (metadata)">

</code-example>



Refresh the browser and see the results.

刷新浏览器，查看结果。



## Select a dashboard hero

## 选择一个*仪表盘*中的英雄

When a user selects a hero in the dashboard, the app should navigate to the `HeroDetailComponent` to view and edit the selected hero.

当用户从仪表盘中选择了一位英雄时，本应用要导航到`HeroDetailComponent`以查看和编辑所选的英雄。

Although the dashboard heroes are presented as button-like blocks, they should behave like anchor tags.
When hovering over a hero block, the target URL should display in the browser status bar
and the user should be able to copy the link or open the hero detail view in a new tab.

虽然仪表盘英雄被显示为像按钮一样的方块，但是它们的行为应该像锚标签一样。
当鼠标移动到一个英雄方块上时，目标 URL 应该显示在浏览器的状态条上，用户应该能拷贝链接或者在新的浏览器标签页中打开英雄详情视图。

To achieve this effect, reopen `dashboard.component.html` and replace the repeated `<div *ngFor...>` tags
with `<a>` tags. Change the opening `<a>` tag to the following:

要达到这个效果，再次打开`dashboard.component.html`，将用来迭代的`<div *ngFor...>`替换为`<a>`，就像这样：


<code-example path="toh-5/src/app/dashboard.component.html" region="click" title="src/app/dashboard.component.html (repeated &lt;a&gt; tag)">

</code-example>



Notice the `[routerLink]` binding.
As described in the [Router links](tutorial/toh-pt5#router-links) section of this page,
top-level navigation in the `AppComponent` template has router links set to fixed paths of the
destination routes, "/dashboard" and "/heroes".

注意`[routerLink]`绑定。正如本章的[Router links](tutorial/toh-pt5#router-links)部分所说，
[`AppComponent`模板](tutorial/toh-pt5#router-links)中的顶级导航有一些路由器链接被设置固定的路径，例如“/dashboard”和“/heroes”。

This time, you're binding to an expression containing a *link parameters array*.
The array has two elements: the *path* of
the destination route and a *route parameter* set to the value of the current hero's `id`.

这次，我们绑定了一个包含**链接参数数组**的表达式。
该数组有两个元素，目标路由和一个用来设置当前英雄的 id 值的**路由参数**。

The two array items align with the *path* and *:id*
token in the parameterized hero detail route definition that you added to
`app.module.ts` earlier:

这两个数组项与之前在`app.module.ts`添加的参数化的英雄详情路由定义中的 ***path*** 和 ***:id*** 对应。


<code-example path="toh-5/src/app/app.module.3.ts" region="hero-detail" title="src/app/app.module.ts (hero detail)">

</code-example>



Refresh the browser and select a hero from the dashboard; the app navigates to that hero’s details.

刷新浏览器，并从仪表盘中选择一位英雄，应用就会直接导航到英雄的详情。



## Refactor routes to a _Routing Module_

## 重构路由为一个**路由模块**
  
Almost 20 lines of `AppModule` are devoted to configuring four routes. 
Most applications have many more routes and they add guard services 
to protect against unwanted or unauthorized navigations. (Read more about guard services in the [Route Guards](guide/router#guards)
section of the [Routing & Navigation](guide/router) page.)
Routing considerations could quickly dominate this module and obscure its primary purpose, which is to 
establish key facts about the entire app for the Angular compiler.

`AppModule`中有将近 20 行代码是用来配置四个路由的。
绝大多数应用有更多路由，并且它们还有守卫服务来保护不希望或未授权的导航。
（要了解守卫服务的更多知识，参见[路由与导航](guide/router)页的[路由守卫](guide/router#guards)）
路由的配置可能迅速占领这个模块，并掩盖其主要目的，即为 Angular 编译器设置整个应用的关键配置。

It's a good idea to refactor the routing configuration into its own class.
The current `RouterModule.forRoot()` produces an Angular `ModuleWithProviders`,
a class dedicated to routing should be a *routing module*.
For more information, see the [Milestone #2: The Routing Module](guide/router#routing-module)
section of the [Routing & Navigation](guide/router) page.

我们应该重构路由配置到它自己的类。
什么样的类呢？
当前的`RouterModule.forRoot()`产生一个Angular `ModuleWithProviders`，所以这个路由类应该是一种模块类。
它应该是一个[**路由模块**](guide/router#routing-module)。要想了解更多，请参阅[路由与导航](guide/router)一章的[里程碑2：路由模块](guide/router#routing-module)部分。

By convention , a routing module name contains the word "Routing" and 
aligns with the name of the module that declares the components navigated to.

按约定，**路由模块**的名字应该包含 “Routing”，并与导航到的组件所在的模块的名称看齐。

Create an `app-routing.module.ts` file as a sibling to `app.module.ts`. Give it the following contents, extracted from the `AppModule` class:

在`app.module.ts`所在目录创建`app-routing.module.ts`文件。将下面从`AppModule`类提取出来的代码拷贝进去：


<code-example path="toh-5/src/app/app-routing.module.ts" title="src/app/app-routing.module.ts">

</code-example>



The following points are typical of routing modules:

典型**路由模块**需要注意的有：
  
* The Routing Module pulls the routes into a variable. The variable clarifies the
  routing module pattern in case you export the module in the future.
  
  将路由抽出到一个变量中。如果你将来要导出这个模块，这种 "路由模块" 的模式也会更加明确。
  
* The Routing Module adds `RouterModule.forRoot(routes)` to `imports`.

  添加`RouterModule.forRoot(routes)`到`imports`。

* The Routing Module adds `RouterModule` to `exports` so that the components in the companion module have access to Router declarables ,
  such as `RouterLink` and `RouterOutlet`.
  
  把`RouterModule`添加到路由模块的`exports`中，以便关联模块（比如`AppModule`）中的组件可以访问路由模块中的声明，比如`RouterLink` 和 `RouterOutlet`。
  
* There are no `declarations`.  Declarations are the responsibility of the companion module.

  无`declarations`！声明是关联模块的任务。

* If you have guard services, the Routing Module adds module `providers`. (There are none in this example.)

  如果有守卫服务，把它们添加到本模块的`providers`中（本例子中没有守卫服务）。

### Update *AppModule*

### 修改 *AppModule*

Delete the routing configuration from `AppModule` and import the `AppRoutingModule`.
Use an ES `import` statement *and* add it to the `NgModule.imports` list.

删除`AppModule`中的路由配置，并导入`AppRoutingModule`
（使用 ES `import`语句导入，**并**将它添加到`NgModule.imports`列表）。

Here is the revised `AppModule`, compared to its pre-refactor state:
  
下面是修改后的`AppModule`，与重构前的对比：


<code-tabs>

  <code-pane title="src/app/app.module.ts (after)" path="toh-5/src/app/app.module.ts">

  </code-pane>

  <code-pane title="src/app/app.module.ts (before)" path="toh-5/src/app/app.module.3.ts">

  </code-pane>

</code-tabs>




## Select a hero in the *HeroesComponent*

## 在 *HeroesComponent* 中选择一位英雄

In the `HeroesComponent`,
the current template exhibits a "master/detail" style with the list of heroes
at the top and details of the selected hero below.

在`HeroesComponent`中，当前模板展示了一个主从风格的界面：上方是英雄列表，底下是所选英雄的详情。


<code-example path="toh-4/src/app/app.component.ts" region="template" title="src/app/heroes.component.ts (current template)" linenums="false">

</code-example>



Delete the `<h1>` at the top.

删除顶部的`<h1>`。

Delete the last line of the template with the `<hero-detail>` tags.

删除模板最后带有`<hero-detail>`标签的那一行。

You'll no longer show the full `HeroDetailComponent` here.
Instead, you'll display the hero detail on its own page and route to it as you did in the dashboard.

我们不在这里展示完整的`HeroDetailComponent`了。
  而是在独立的路由和页面中显示英雄详情，就像我们在仪表盘中所做的那样。

However, when users select a hero from the list, they won't go to the detail page.
Instead, they'll see a mini detail on *this* page and have to click a button to navigate to the *full detail* page.

但是，当用户从列表中选择一个英雄时，他们不会在导航到详情页，
而是在*当前页*显示一个Mini版详情视图，当用户点击一个按钮时，才导航到*完整的详情*页面。

### Add the *mini detail*

### 添加 *mini 版英雄详情*

Add the following HTML fragment at the bottom of the template where the `<hero-detail>` used to be:

在模板底部原来放`<hero-detail>`的地方添加下列 HTML 片段：


<code-example path="toh-5/src/app/heroes.component.html" region="mini-detail" title="src/app/heroes.component.ts">

</code-example>



After clicking a hero, users should see something like this below the hero list:

点击一个英雄，用户将会在英雄列表的下方看到这些：


<figure class='image-display'>
  <img src='assets/images/devguide/toh/mini-hero-detail.png' alt="Mini版英雄" height="70"></img>
</figure>



### Format with the uppercase pipe

### 使用*uppercase*管道格式化

The hero's name is displayed in capital letters because of the `uppercase` pipe
that's included in the interpolation binding, right after the pipe operator ( | ).

注意，英雄的名字全被显示成大写字母。那是`uppercase`管道的效果，借助它，我们能干预插值表达式绑定的过程。可以管道操作符 ( | ) 后面看到它。


<code-example path="toh-5/src/app/heroes.component.html" region="pipe">

</code-example>



Pipes are a good way to format strings, currency amounts, dates and other display data.
Angular ships with several pipes and you can write your own.

管道擅长做下列工作：格式化字符串、金额、日期和其它显示数据。
Angular 自带了一些管道，我们也可以写自己的管道。


<div class="l-sub-section">



Read more about pipes on the [Pipes](guide/pipes) page.

关于管道的更多信息，参见[管道](guide/pipes)。


</div>



### Move content out of the component file

### 把内容移出组件文件

You still have to update the component class to support navigation to the
`HeroDetailComponent` when users click the *View Details* button.

当用户点击*查看详情*按钮时，要让它能导航到`HeroDetailComponent`，我们还需要修改它。

The component file is big.
It's difficult to find the component logic amidst the noise of HTML and CSS.

这个组件文件太大了。要想在 HTML 和 CSS 的噪音中看清组件的工作逻辑太难了。

Before making any more changes, migrate the template and styles to their own files. 

在做更多修改之前，我们先把模板和样式移到它们自己的文件中去：

First, move the template contents from `heroes.component.ts` 
into a new <code>heroes.component.html</code> file. 
Don't copy the backticks. As for `heroes.component.ts`, you'll 
come back to it in a minute. Next, move the 
styles contents into a new <code>heroes.component.css</code> file.

首先，从`heroes.component.ts`中把模板内容移到新的<code>heroes.component.html</code>文件中，但不要把反引号也拷贝过去。就像`heroes.component.ts`一样，我们很快就能做完。接着，把样式的内容移到新的<code>heroes.component.css</code>文件中。

The two new files should look like this:

这两个新文件是这样的：


<code-tabs>

  <code-pane title="src/app/heroes.component.html" path="toh-5/src/app/heroes.component.html">

  </code-pane>

  <code-pane title="src/app/heroes.component.css" path="toh-5/src/app/heroes.component.css">

  </code-pane>

</code-tabs>



Now, back in the component metadata for `heroes.component.ts`, 
delete `template` and `styles`, replacing them with 
`templateUrl` and `styleUrls` respectively.
Set their properties to refer to the new files.

现在，回来编辑`heroes.component.ts`中的组件元数据，删除`template` 和 `styles`属性，代之以相应的`templateUrl` 和 `styleUrls`属性。让它们指向这些新文件。


<code-example path="toh-5/src/app/heroes.component.ts" region="metadata" title="src/app/heroes.component.ts (revised metadata)">

</code-example>



<div class="l-sub-section">



The `styleUrls` property is an array of style file names (with paths).
You could list multiple style files from different locations if you needed them.

`styleUrls`属性是一个由样式文件的文件名(包括路径)组成的数组。我们还可以列出来自多个不同位置的样式文件。


</div>



### Update the _HeroesComponent_ class

### 更新 _HeroesComponent_ 类

The `HeroesComponent` navigates to the `HeroesDetailComponent` in response to a button click.
The button's click event is bound to a `gotoDetail()` method that navigates _imperatively_
by telling the router where to go.

点击按钮时，`HeroesComponent`导航到`HeroDetailComponent`。
该按钮的点击事件绑定到了`gotoDetail()`方法，它使用命令式的导航，告诉路由器去哪儿。

This approach requires the following changes to the component class:

该方法需要对组件类做一些修改：

1. Import the `Router` from the Angular router library.

  从 Angular 路由器库导入`Router`
  
1. Inject the `Router` in the constructor, along with the `HeroService`.

  在构造函数中注入`Router`（与`HeroService`一起）
  
1. Implement `gotoDetail()` by calling the router `navigate()` method.

   实现`gotoDetail()`，调用路由器的`navigate()`方法


<code-example path="toh-5/src/app/heroes.component.ts" region="gotoDetail" title="src/app/heroes.component.ts (gotoDetail)">

</code-example>



Note that you're passing a two-element *link parameters array*&mdash;a
path and the route parameter&mdash;to
the router `navigate()` method, just as you did in the `[routerLink]` binding
back in the `DashboardComponent`.
Here's the revised `HeroesComponent` class:

注意，我们将一个包含两个元素的**链接参数数组** &mdash; 
路径和路由参数 &mdash; 传递到路由的`navigate（）`，
与之前在`DashboardComponent`中使用`[routerLink]`绑定一样。
修改完成的`HeroesComponent`类如下所示：


<code-example path="toh-5/src/app/heroes.component.ts" region="class" title="src/app/heroes.component.ts (class)">

</code-example>



Refresh the browser and start clicking.
Users can navigate around the app, from the dashboard to hero details and back,
from heroes list to the mini detail to the hero details and back to the heroes again.

刷新浏览器，并开始点击。
  我们能在应用中导航：从仪表盘到英雄详情再回来，从英雄列表到 mini 版英雄详情到英雄详情，再回到英雄列表。
  我们可以在仪表盘和英雄列表之间跳来跳去。

You've met all of the navigational requirements that propelled this page.

我们已经满足了在本章开头设定的所有导航需求。



## Style the app

## 美化本应用

The app is functional but it needs styling.
The dashboard heroes should display in a row of rectangles.
You've received around 60 lines of CSS for this purpose, including some simple media queries for responsive design.

应用在功能上已经正常了，但还需要美化。
仪表盘上的英雄应该显示在一行上的几个方块中。
我们拿到了大约60行CSS来完成这件事，包括一些简单的媒体查询代码以实现响应式设计。

As you now know, adding the CSS to the component `styles` metadata
would obscure the component logic.
Instead, edit the CSS in a separate `*.css` file.

我们不能把这 60 来行 CSS 粘贴到组件元数据的`styles`中，否则它会淹没组件的工作逻辑。反之，我们应该在独立的`*.css`文件中编辑这些CSS。

Add a <code>dashboard.component.css</code> file to the `app` folder and reference
that file in the component metadata's `styleUrls` array property like this:

把<code>dashboard.component.css</code>文件添加到`app`目录下，并在组件元数据的`styleUrls`数组属性中引用它。就像这样：


<code-example path="toh-5/src/app/dashboard.component.ts" region="css" title="src/app/dashboard.component.ts (styleUrls)">

</code-example>



### Add stylish hero details

### 美化英雄详情

You've also been provided with CSS styles specifically for the `HeroDetailComponent`.

我们还拿到了一些`HeroDetailComponent`特有的 CSS 风格。

Add a <code>hero-detail.component.css</code> to the `app`
folder and refer to that file inside
the `styleUrls` array as you did for `DashboardComponent`.
Also, in `hero-detail.component.ts`, remove the `hero` property `@Input` decorator
and its import.

在`app`目录下添加<span ngio-ex>hero-detail.component.css</span>文件，
并且在`styleUrls`数组中引用它 —— 就像之前在`DashboardComponent`中做过的那样。
同时删除`hero``@Input`装饰器属性和它的导入语句。

Here's the content for the component CSS files.

上述组件的 CSS 文件内容如下：


<code-tabs>

  <code-pane title="src/app/hero-detail.component.css" path="toh-5/src/app/hero-detail.component.css">

  </code-pane>

  <code-pane title="src/app/dashboard.component.css" path="toh-5/src/app/dashboard.component.css">

  </code-pane>

</code-tabs>



### Style the navigation links

### 美化导航链接

The provided CSS makes the navigation links in the `AppComponent` look more like selectable buttons.
You'll surround those links in `<nav>` tags.

设计师还给了我们一些 CSS，用于让`AppComponent`中的导航链接看起来更像可被选择的按钮。
要让它们协同工作，我们得把那些链接包含在`<nav>`标签中。

Add an <code>app.component.css</code> file to the `app` folder with the following content.

在`app`目录下添加一个<span ngio-ex>app.component.css</span>文件，内容如下：


<code-example path="toh-5/src/app/app.component.css" title="src/app/app.component.css (navigation styles)">

</code-example>



<div class="l-sub-section">



**The *routerLinkActive* directive**

***routerLinkActive*指令**

The Angular router provides a `routerLinkActive` directive you can use to
  add a class to the HTML navigation element whose route matches the active route.
  All you have to do is define the style for it. 

Angular路由器提供了`routerLinkActive`指令，我们可以用它来为匹配了活动路由的 HTML 导航元素自动添加一个 CSS 类。
  我们唯一要做的就是为它定义样式。真好！
  

<code-example path="toh-5/src/app/app.component.ts" region="template" title="src/app/app.component.ts (active router links)">

</code-example>



</div>



Add a `styleUrls` property that refers to this CSS file as follows:

首先把`moduleId: module.id`添加到`AppComponent`组件的`@Component`元数据中以启用*相对于模块的*文件URL。
然后添加`styleUrls`属性，使其指向这个CSS文件，代码如下：


<code-example path="toh-5/src/app/app.component.ts" region="styleUrls" title="toh-5/src/app/app.component.ts">

</code-example>



### Global application styles

### 应用的全局样式

When you add styles to a component, you keep everything a component needs&mdash;HTML,
the CSS, the code&mdash;together in one convenient place.
It's easy to package it all up and re-use the component somewhere else.

当我们把样式添加到组件中时，我们假定组件所需的一切 &mdash; HTML、CSS、程序代码 &mdash; 都在紧邻的地方。
  这样，无论是把它们打包在一起还是在别的组件中复用它都会很容易。

You can also create styles at the *application level* outside of any component.

我们也可以在所有组件之外创建*应用级*样式。

The designers provided some basic styles to apply to elements across the entire app.
These correspond to the full set of master styles that you installed earlier during [setup](guide/setup).
Here's an excerpt:

我们的设计师提供了一组基础样式，这些样式应用到的元素横跨整个应用。
它们与我们之前在[开发环境](guide/setup)时安装的整套样式对应。
下面是摘录：


<code-example path="toh-5/src/styles.css" region="toh" title="src/styles.css (excerpt)">

</code-example>



Create the file <code>styles.css</code>.
Ensure that the file contains the [master styles provided here](https://raw.githubusercontent.com/angular/angular.io/master/public/docs/_examples/_boilerplate/src/styles.css).
Also edit <code>index.html</code> to refer to this stylesheet.

如果在根目录下没有一个名叫`styles.css`的文件，就添加它。
确保它包含[这里给出的主样式](https://raw.githubusercontent.com/angular/angular.io/master/public/docs/_examples/_boilerplate/src/styles.css)。
并编辑`index.html`来引用这个样式表。


<code-example path="toh-5/src/index.html" region="css" title="src/index.html (link ref)">

</code-example>



Look at the app now. The dashboard, heroes, and navigation links are styled.

看看现在的应用！我们的仪表盘、英雄列表和导航链接都漂亮多了！


<figure class='image-display'>
  <img src='assets/images/devguide/toh/heroes-dashboard-1.png' alt="查看导航栏"></img>
</figure>




## Application structure and code

## 应用结构和代码

Review the sample source code in the <live-example></live-example> for this page.
Verify that you have the following structure:

回顾一下本章<live-example></live-example>中范例代码。
  验证我们是否已经得到了如下结构：


<div class='filetree'>

  <div class='file'>
    angular-tour-of-heroes
  </div>

  <div class='children'>

    <div class='file'>
      src
    </div>

    <div class='children'>

      <div class='file'>
        app
      </div>

      <div class='children'>

        <div class='file'>
          app.component.css
        </div>

        <div class='file'>
          app.component.ts
        </div>

        <div class='file'>
          app.module.ts
        </div>

        <div class='file'>
          app-routing.module.ts
        </div>

        <div class='file'>
          dashboard.component.css
        </div>

        <div class='file'>
          dashboard.component.html
        </div>

        <div class='file'>
          dashboard.component.ts
        </div>

        <div class='file'>
          hero.service.ts
        </div>

        <div class='file'>
          hero.ts
        </div>

        <div class='file'>
          hero-detail.component.css
        </div>

        <div class='file'>
          hero-detail.component.html
        </div>

        <div class='file'>
          hero-detail.component.ts
        </div>

        <div class='file'>
          heroes.component.css
        </div>

        <div class='file'>
          heroes.component.html
        </div>

        <div class='file'>
          heroes.component.ts
        </div>

        <div class='file'>
          mock-heroes.ts
        </div>

      </div>

      <div class='file'>
        main.ts
      </div>

      <div class='file'>
        index.html
      </div>

      <div class='file'>
        styles.css
      </div>

      <div class='file'>
        systemjs.config.js
      </div>

      <div class='file'>
        tsconfig.json
      </div>

    </div>

    <div class='file'>
      node_modules ...
    </div>

    <div class='file'>
      package.json
    </div>

  </div>

</div>




## The road you’ve travelled

## 走过的路

Here's what you achieved in this page:

本章中我们完成了这些：

* You added the Angular router to navigate among different components.

  添加了 Angular *路由器*在各个不同组件之间导航。
  
* You learned how to create router links to represent navigation menu items.

  学会了如何创建路由链接来表示导航栏的菜单项。
  
* You used router link parameters to navigate to the details of the user-selected hero.

  使用路由链接参数来导航到用户所选的英雄详情。
  
* You shared the `HeroService` among multiple components.

  在多个组件之间共享了`HeroService`服务。
  
* You moved HTML and CSS out of the component file and into their own files.

  把 HTML 和 CSS 从组件中移出来，放到了它们自己的文件中。
  
* You added the `uppercase` pipe to format data.

  添加了`uppercase`管道，来格式化数据。
  
Your app should look like this <live-example></live-example>.

我们的应用现在变成了这样：<live-example></live-example>。

### The road ahead

### 前方的路

You have much of the foundation you need to build an app.
You're still missing a key piece: remote data access.

我们有了很多用于构建应用的基石。
  但我们仍然缺少很关键的一块：远程数据存取。

In the next page,
you’ll replace the mock data with data retrieved from a server using http.

在下一章，我们将从硬编码模拟数据改为使用 http 服务从服务器获取数据。