parent
347c79c514
commit
f7b2913231
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@ -184,7 +184,7 @@
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<input type="text" class="form-control" required
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[(ng-model)]="model.name"
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ng-control="name" #spy >
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TODO: remove this: {{spy.className}}
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<br>TODO: remove this: {{spy.className}}
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<!-- #enddocregion ng-control-2 -->
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</form>
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@ -1,16 +1,13 @@
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// #docplaster
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// #docregion
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// #docregion first, final
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import {Component, CORE_DIRECTIVES, FORM_DIRECTIVES} from 'angular2/angular2';
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import {Component} from 'angular2/angular2';
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import { Hero } from './hero';
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@Component({
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selector: 'hero-form',
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templateUrl: 'app/hero-form.component.html',
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// #docregion directives
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directives: [CORE_DIRECTIVES, FORM_DIRECTIVES]
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// #enddocregion
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templateUrl: 'app/hero-form.component.html'
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})
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export class HeroFormComponent {
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@ -18,29 +18,29 @@ include ../../../../_includes/_util-fns
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We will build a simple form from scratch, one step at a time. Along the way we'll learn
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- how to build an Angular form with a component and template
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- How to build an Angular form with a component and template
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- the `ng-model` two-way data binding syntax for reading and writing values to input controls
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- The `ng-model` two-way data binding syntax for reading and writing values to input controls
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- the `ng-control` directive to track the change state and validity of form controls
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- The `ng-control` directive to track the change state and validity of form controls
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- the special CSS classes that `ng-control` adds to form controls and how we can use them to provide strong visual feedback
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- The special CSS classes that `ng-control` adds to form controls and how we can use them to provide strong visual feedback
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- how to display validation errors to users and enable/disable form controls
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- How to display validation errors to users and enable/disable form controls
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- how to share information across controls with template local variables
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- How to share information across controls with template local variables
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.l-main-section
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:marked
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## Template-Driven Forms
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Many of us will build forms by writing templates in the Angular [template syntax](./template-syntax.html) with
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the form-specific Directives and techniques described in this chapter.
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the form-specific directives and techniques described in this chapter.
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.l-sub-section
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:marked
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That's not the only way to create a form but it's the way we'll cover in this chapter.
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:marked
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We can build almost any form we need with an Angular template ... login forms, contact forms ... pretty much any business forms.
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We can build almost any form we need with an Angular template $mdash; login forms, contact forms ... pretty much any business forms.
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We can lay out the controls creatively, bind them to data, specify validation rules and display validation errors,
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conditionally enable or disable specific controls, trigger built-in visual feedback, and much more.
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@ -50,7 +50,7 @@ include ../../../../_includes/_util-fns
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We'll discuss and learn to build the following template-driven form:
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figure.image-display
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img(src="/resources/images/devguide/forms/hf-1.png" alt="Clean Form")
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img(src="/resources/images/devguide/forms/hf-1.png" width="400px" alt="Clean Form")
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:marked
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Here at the *Hero Employment Agency* we use this form to maintain personal information about the
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@ -61,7 +61,7 @@ figure.image-display
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If we delete the hero name, the form displays a validation error in an attention grabbing style:
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figure.image-display
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img(src="/resources/images/devguide/forms/hf-2.png" alt="Invalid, Name Required")
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img(src="/resources/images/devguide/forms/hf-2.png" width="400px" alt="Invalid, Name Required")
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:marked
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Note that the submit button is disabled and the "required" bar to the left of the input control changed from green to red.
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@ -95,20 +95,23 @@ figure.image-display
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That describes well our `Hero` class with its three required fields (`id`, `name`, `power`)
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and one optional field (`alterEgo`).
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Create a new file called `hero.ts` and give it the following class definition:
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Create a new file in the app folder called `hero.ts` and give it the following class definition:
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+makeExample('forms/ts/src/app/hero.ts')
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+makeExample('forms/ts/src/app/hero.ts', null, 'hero.ts')
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:marked
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It's an anemic model with few requirements and no behavior. Perfect for our demo.
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The TypeScript compiler generates a public field for each `public` constructor parameter and
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assigns the parameter’s value to that field automatically when we create new heroes like this:
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assigns the parameter’s value to that field automatically when we create new heroes.
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The `alterEgo` is optional and the constructor lets us omit it; note the (?) in `alterEgo?`.
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We can create a new hero like this:
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```
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let myHero = new Hero(42, 'SkyDog', 'Fetch any object at any distance', 'Leslie Rollover');
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console.log('My hero is called ' + myHero.name); // "My hero is called SkyDog"
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```
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The `alterEgo` is optional and the constructor lets us omit it; note the (?) in `alterEgo?`.
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.l-main-section
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:marked
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@ -120,17 +123,14 @@ figure.image-display
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Create a new file called `hero-form.component.ts` and give it the following definition:
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+makeExample('forms/ts/src/app/hero-form.component.ts', 'first')
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+makeExample('forms/ts/src/app/hero-form.component.ts', 'first', 'app/hero-form.component.ts (v.1)')
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:marked
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There’s nothing special about this component, nothing to distinguish it from any component we've written before,
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nothing form-specific about it ... except, perhaps, the tell-tale `FORM_DIRECTIVES` import.
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There’s nothing special about this component, nothing form-specific, nothing to distinguish it from any component we've written before.
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Understanding this component requires only the Angular 2 concepts we’ve learned in previous chapters
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1. We import a standard set of symbols from the Angular library.
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We don't have a template yet but we usually import `CORE_DIRECTIVES` and it doesn't surprise us to
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import something called `FORM_DIRECTIVES`, given that we'll be writing a form
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1. We import the `Component` decorator from the Angular library as we usually do.
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1. The `@Component` selector value of "hero-form" means we can drop this form in a parent template with a `<hero-form>` tag.
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@ -144,15 +144,17 @@ figure.image-display
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1. We threw in a `diagnostic` property at the end to return a JSON representation of our model.
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It'll help us see what we're doing during our development; we've left ourselves a cleanup note to discard it later.
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We may wonder why we aren't writing the template inline in the component file as we have often done
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elsewhere in the Developer Guide.
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Why don't we write the template inline in the component file as we often do
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elsewhere in the Developer Guide?
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There is no “right” answer for all occasions. We kind of like inline templates when they are short.
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There is no “right” answer for all occasions. We like inline templates when they are short.
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Most form templates won't be short. TypeScript and JavaScript files generally aren't the best place to
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write (or read) large stretches of HTML and few editors are much help with files that have a mix of HTML and code.
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We also like short files with a clear and obvious purpose like this one.
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We made a good choice to put the HTML template elsewhere. Let's write it.
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We made a good choice to put the HTML template elsewhere.
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We'll write that template in a moment. Before we do, we'll take a step back
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and revise the `app.ts` to make use of our new `HeroFormComponent`.
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.l-main-section
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:marked
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`app.ts` is the application's root component. It will host our new `HeroFormComponent`.
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Replace the contents of the "QuickStart" version with the following:
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+makeExample('forms/ts/src/app/app.ts')
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+makeExample('forms/ts/src/app/app.ts', null, 'app.ts')
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:marked
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.l-sub-section
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@ -181,43 +183,41 @@ figure.image-display
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Create a new template file called `hero-form.component.html` and give it the following definition:
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+makeExample('forms/ts/src/app/hero-form.component.html', 'start')
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+makeExample('forms/ts/src/app/hero-form.component.html', 'start', 'app/hero-form.component.html (v.1)')
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:marked
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That is plain old HTML 5. We're presenting two of the `Hero` fields, `name` and `alterEgo`, and
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opening them up for user input in input boxes.
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The "Name" `<input>` control has the HTML5 `required` attribute;
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the "Alter Ego" `<input>` control does not because `alterEgo` is optional.
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The *Name* `<input>` control has the HTML5 `required` attribute;
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the *Alter Ego* `<input>` control does not because `alterEgo` is optional.
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We've got a "Submit" button at the bottom with some classes on it.
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We've got a *Submit* button at the bottom with some classes on it.
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**We are not using Angular yet**. There are no bindings. No extra directives. Just layout.
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The `container`,`form-group`, `form-control`, and `btn` classes are CSS Bootstrap. Purely cosmetic.
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The `container`,`form-group`, `form-control`, and `btn` classes
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come from [Twitter Boostrap](http://getbootstrap.com/css/). Purely cosmetic.
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We're using Bootstrap to gussy up our form.
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Hey, what's a form without a little style!
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.l-sub-section
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:marked
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Since we're using [CSS Boostrap](http://getbootstrap.com/css/).
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now might be a good time to install it into our project.
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We can do that with npm.
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Open a terminal window and enter the command:
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code-example(language="html" escape="html").
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npm install bootstrap
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:marked
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<br>Open the `index.html` and add the following line wherever we like to put our CSS
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+makeExample('forms/ts/src/index.html', 'bootstrap')(format=".")
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.callout.is-important
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header Angular Forms Does Not Require A Style Library
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header Angular Forms Do Not Require A Style Library
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:marked
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Angular makes no use of the `container`, `form-group`, `form-control`, and `btn` classes or
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the styles of any external library. We are welcome to use the CSS library we choose
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the styles of any external library. Angular apps can use any CSS library
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... or none at all.
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:marked
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Let's add the stylesheet.
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ol
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li Open a terminal window and enter the command:
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code-example(language="html" escape="html").
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npm install bootstrap --save
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li Open <code>index.html</code> and add the following link to the <code><head></code>.
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+makeExample('forms/ts/src/index.html', 'bootstrap')(format=".")
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:marked
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.l-main-section
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:marked
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## Add Powers with ***ng-for**
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@ -226,10 +226,10 @@ figure.image-display
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We'll add a `select` to our
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form and bind the options to the `powers` list using `NgFor`,
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a technique we might have seen before in the ["Displaying Data"](./displaying-data.html) chapter.
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a technique we might have seen before in the [Displaying Data](./displaying-data.html) chapter.
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Add the following HTML *immediately below* the "Alter Ego" group.
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+makeExample('forms/ts/src/app/hero-form.component.html', 'powers')
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Add the following HTML *immediately below* the *Alter Ego* group.
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+makeExample('forms/ts/src/app/hero-form.component.html', 'powers', 'app/hero-form.component.html (excerpt)')
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:marked
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We are repeating the `<options>` tag for each power in the list of Powers.
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|
@ -239,17 +239,16 @@ figure.image-display
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.l-main-section
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:marked
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## Two-way data binding with ***ng-model**
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We might be disappointed if we ran the app right now.
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Running the app right now would be disappointing.
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figure.image-display
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img(src="/resources/images/devguide/forms/hf-3.png" alt="Early form with no binding")
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img(src="/resources/images/devguide/forms/hf-3.png" width="400px" alt="Early form with no binding")
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:marked
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We quickly realize that we are not binding to the `Hero` yet.
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We don't see hero data because we are not binding to the `Hero` yet.
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We know how to do that from earlier chapters.
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We learned show data on screen with a Property Binding in "[Displaying Data](./displaying-data.html)".
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We learned to listen for DOM events with an
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Event Binding and how to extract values from the screen
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in "[User Input](./user-input.html)".
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[Displaying Data](./displaying-data.html) taught us Property Binding.
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[User Input](./user-input.html) showed us how to listen for DOM events with an
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Event Binding and how to update a component property with the displayed value.
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||||
Now we need to display, listen, and extract at the same time.
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|
@ -270,54 +269,48 @@ figure.image-display
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:marked
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Focus on the binding syntax: `[(ng-model)]="..."`.
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If we ran the app right now and started typing in the "Name" input box,
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If we ran the app right now and started typing in the *Name* input box,
|
||||
adding and deleting characters, we'd see them appearing and disappearing
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from the interpolated text.
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At some point it might look like this.
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figure.image-display
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img(src="/resources/images/devguide/forms/ng-model-in-action.png" alt="ng-model in action")
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img(src="/resources/images/devguide/forms/ng-model-in-action.png" width="400px" alt="ng-model in action")
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:marked
|
||||
The diagnostic is evidence that we really are flowing values from the input box to the model and
|
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back again. **That's two-way data binding!**
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||||
|
||||
Let's add similar `[(ng-model)]` bindings to "Alter Ego" and "Hero Power".
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||||
Let's add similar `[(ng-model)]` bindings to *Alter Ego* and *Hero Power*.
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We'll ditch the input box binding message
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and add a new binding at the top to the component's `diagnostic` property.
|
||||
Then we can confirm that we are in fact two-way data binding *to the entire Hero model*.
|
||||
Then we can confirm that two-way data binding works *for the entire Hero model*.
|
||||
|
||||
After revision the core of our form should have three `[(ng-model)]` bindings that
|
||||
look much like this:
|
||||
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-model-2')
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||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-model-2', 'app/hero-form.component.html (excerpt)')
|
||||
|
||||
:marked
|
||||
If we ran the app right now and made a bunch of changes at some point it might look like this.
|
||||
If we ran the app right now and changed every Hero model property, the form might display like this:
|
||||
figure.image-display
|
||||
img(src="/resources/images/devguide/forms/ng-model-in-action-2.png" alt="ng-model in super action")
|
||||
img(src="/resources/images/devguide/forms/ng-model-in-action-2.png" width="400px" alt="ng-model in super action")
|
||||
:marked
|
||||
We've changed every Hero model property and the diagnostic near the top of the form
|
||||
confirms that our changes are reflected in the model.
|
||||
The diagnostic near the top of the form
|
||||
confirms that all of our changes are reflected in the model.
|
||||
|
||||
** We're done with the diagnostic binding. Delete it now.**
|
||||
|
||||
.alert.is-helpful
|
||||
:marked
|
||||
Although `NgModel` is officially a "Forms" directive we can use `[(ng-model)]` and two-way binding outside of forms too.
|
||||
:marked
|
||||
## Inside [(ng-model)]
|
||||
Do we *really want* to know? If we're just happy that it works, move on to the next topic in this chapter.
|
||||
|
||||
Otherwise, stick around for this note.
|
||||
|
||||
.l-sub-section
|
||||
:marked
|
||||
### Inside [(ng-model)]
|
||||
*This section is an optional deep dive into [(ng-model)]. Not interested? Skip ahead!*
|
||||
|
||||
The punctuation in the binding syntax, <span style="font-family:courier"><b>[()]</b></span>, is a good clue to what's going on.
|
||||
|
||||
We write a Property Binding to flow data from the model to a target property on screen.
|
||||
In a Property Binding, a value flows from the model to a target property on screen.
|
||||
We identify that target property by surrounding its name in brackets, <span style="font-family:courier"><b>[]</b></span>.
|
||||
This is a one-way data binding **from the model to the view**.
|
||||
|
||||
We write an Event Binding to flow data from the target property on screen to the model.
|
||||
In an Event Binding, we flow the value from the target property on screen to the model.
|
||||
We identify that target property by surrounding its name in parentheses, <span style="font-family:courier"><b>()</b></span>.
|
||||
This is a one-way data binding in the opposite direction **from the view to the model**.
|
||||
|
||||
|
@ -331,18 +324,18 @@ figure.image-display
|
|||
:marked
|
||||
<br>The Property Binding should feel familiar. The Event Binding might seem strange.
|
||||
|
||||
The name `ng-model-change` is not an event we recognize.
|
||||
It is a real event property ... of the `NgModel` directive.
|
||||
The `ng-model-change` is not an `<input>` element event.
|
||||
It is actually an event property of the `NgModel` directive.
|
||||
When Angular sees a binding target in the form <span style="font-family:courier">[(abc)]</span>,
|
||||
it expects the `abc` directive to have an `abc` input property and an `abc-change` output property.
|
||||
|
||||
The other oddity is the template expression, `model.name = $event`.
|
||||
We're used to seeing an `$event` object coming from a DOM event.
|
||||
The `ng-model-change` property doesn't produce a DOM event; it's an Angular `EventEmitter`
|
||||
property that returns the input box value when it fires ... which is precisely what
|
||||
property that returns the input box value when it fires — which is precisely what
|
||||
we should assign to the model's `name' property.
|
||||
|
||||
Nice to know but is it practical? We'd always prefer the `[(ng-model)]`.
|
||||
Nice to know but is it practical? We almost always prefer `[(ng-model)]`.
|
||||
We might split the binding if we had to do something special in
|
||||
the event handling such as debounce or throttle the key strokes.
|
||||
|
||||
|
@ -362,10 +355,8 @@ figure.image-display
|
|||
The `NgControl` is one of a family of `NgForm` directives that can only be applied to
|
||||
a control within a `<form`> tag.
|
||||
:marked
|
||||
Our application can ask an `NgControl` instance if
|
||||
* the user touched the control (`ng-touched` | `ng-untouched`)
|
||||
* the value changed (`ng-pristine` | `ng-dirty`)
|
||||
* is the value is valid (`ng-valid` | `ng-invalid`)
|
||||
Our application can ask an `NgControl` if the user touched the control,
|
||||
if the value changed, or if the value became invalid.
|
||||
|
||||
`NgControl` doesn't just track state; it updates the control with special
|
||||
Angular CSS classes from the set we listed above.
|
||||
|
@ -373,9 +364,9 @@ figure.image-display
|
|||
control and make messages appear or disappear.
|
||||
|
||||
We'll explore those effects soon. Right now
|
||||
we should **add `ng-control`to all three of our form controls**,
|
||||
starting with the "Name" input box
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-control-1')
|
||||
we should **add `ng-control`to all three form controls**,
|
||||
starting with the *Name* input box
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-control-1', 'app/hero-form.component.html (excerpt)')
|
||||
:marked
|
||||
Be sure to assign a unique name to each `ng-control` directive.
|
||||
|
||||
|
@ -384,34 +375,54 @@ figure.image-display
|
|||
Angular registers controls under their `ng-control` names
|
||||
with the `NgForm`.
|
||||
We didn't add the `NgForm` directive explicitly but it's here
|
||||
and we'll talk it [later in this chapter](#ng-form).
|
||||
and we'll talk about it [later in this chapter](#ng-form).
|
||||
|
||||
.l-main-section
|
||||
:marked
|
||||
## Add Custom CSS for Visual Feedback
|
||||
|
||||
`NgControl` doesn't just track state. It updates the control with three classes, one
|
||||
each from the following pairs of Angular form CSS classes.
|
||||
* control visited: (`ng-touched` | `ng-untouched`)
|
||||
* value changed: (`ng-pristine` | `ng-dirty`)
|
||||
* validity: (`ng-valid` | `ng-invalid`)
|
||||
`NgControl` doesn't just track state.
|
||||
It updates the control with three classes that reflect the state.
|
||||
|
||||
table
|
||||
tr
|
||||
th State
|
||||
th Class if true
|
||||
th Class if false
|
||||
tr
|
||||
td Control has been visited
|
||||
td <code>ng-touched</code>
|
||||
td <code>ng-untouched</code>
|
||||
tr
|
||||
td Control's value has changed
|
||||
td <code>ng-dirty</code>
|
||||
td <code>ng-pristine</code>
|
||||
tr
|
||||
td Control's value is valid
|
||||
td <code>ng-valid</code>
|
||||
td <code>ng-invalid</code>
|
||||
:marked
|
||||
Let's add a temporary [local template variable](./template-syntax.html#local-vars) named **spy**
|
||||
to the "Name" `<input>` tag and use the spy to display those classes with an interpolation binding.
|
||||
to the "Name" `<input>` tag and use the spy to display those classes.
|
||||
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-control-2')
|
||||
|
||||
:marked
|
||||
If we ran the app, focused our attention on the "Name" input box, and followed the next four steps *precisely*
|
||||
Now run the app and focus on the *Name* input box.
|
||||
Follow the next four steps *precisely*
|
||||
|
||||
1. Look but don't touched
|
||||
1. Click in the input box, then click outside the text input box
|
||||
1. Add slashes to the end of the name
|
||||
1. Erase the name
|
||||
|
||||
... we would see the following four sets of class names and their transitions:
|
||||
The actions and effects are as follows:
|
||||
figure.image-display
|
||||
img(src="/resources/images/devguide/forms/ng-control-class-changes.png" alt="Invalid Form")
|
||||
img(src="/resources/images/devguide/forms/control-state-transitions-anim.gif" alt="Control State Transition")
|
||||
:marked
|
||||
We should be able to see the following four sets of class names and their transitions:
|
||||
figure.image-display
|
||||
img(src="/resources/images/devguide/forms/ng-control-class-changes.png" width="400px" alt="Control State Transitions")
|
||||
|
||||
:marked
|
||||
The (`ng-valid` | `ng-invalid`) pair are most interesting to us. We want to send a
|
||||
|
@ -420,18 +431,18 @@ figure.image-display
|
|||
We realize we can do both at the same time with a colored bar on the left of the input box:
|
||||
|
||||
figure.image-display
|
||||
img(src="/resources/images/devguide/forms/validity-required-indicator.png" alt="Invalid Form")
|
||||
img(src="/resources/images/devguide/forms/validity-required-indicator.png" width="400px" alt="Invalid Form")
|
||||
|
||||
:marked
|
||||
We achieve this effect by adding two styles to a new `styles.css` file
|
||||
that we add to our project as a sibling to `index.html`.
|
||||
|
||||
+makeExample('forms/ts/src/styles.css')
|
||||
+makeExample('forms/ts/src/styles.css',null,'styles.css')
|
||||
:marked
|
||||
These styles select for the two Angular validity classes and the HTML 5 "required" attribute.
|
||||
|
||||
We update the `<head>` of the `index.html` to include this style sheet.
|
||||
+makeExample('forms/ts/src/index.html', 'styles')(format=".")
|
||||
+makeExample('forms/ts/src/index.html', 'styles', 'index.html (excerpt)')(format=".")
|
||||
:marked
|
||||
## Show and Hide Validation Error messages
|
||||
|
||||
|
@ -443,15 +454,19 @@ figure.image-display
|
|||
|
||||
Here's the way it should look when the user deletes the name:
|
||||
figure.image-display
|
||||
img(src="/resources/images/devguide/forms/name-required-error.png" alt="Name required")
|
||||
img(src="/resources/images/devguide/forms/name-required-error.png" width="400px" alt="Name required")
|
||||
|
||||
:marked
|
||||
To achieve this effect we extend the `<input>` tag with
|
||||
1. a [local template variable](./template-syntax.html#local-vars)
|
||||
1. the "*is required*" message in a nearby `<div>` which we'll display only if the control is invalid.
|
||||
|
||||
Here's how we do it for the "name" input box:
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'name-with-error-msg')
|
||||
Here's how we do it for the *name* input box:
|
||||
-var stylePattern = { otl: /(#name="form")|(.*div.*$)|(Name is required)/gm };
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html',
|
||||
'name-with-error-msg',
|
||||
'app/hero-form.component.html (excerpt)',
|
||||
stylePattern)
|
||||
:marked
|
||||
We initialized the template local variable with the word "form" (`#name="form"`)
|
||||
|
||||
|
@ -465,16 +480,13 @@ figure.image-display
|
|||
<a id="ng-form"></a>
|
||||
.l-sub-section
|
||||
:marked
|
||||
### The NgForm directive
|
||||
Recall from the previous section that `ng-control` registered this input box with the
|
||||
`NgForm` directive as "name".
|
||||
|
||||
We didn't add the **[`NgForm`](../api/core/NgForm-class.html) directive** explicitly.
|
||||
Angular added it surreptiously, wrapping it around the `<form>` element when we
|
||||
told the `HeroFormComponent` to use the `FORM_DIRECTIVES` like this
|
||||
Angular added it surreptiously, wrapping it around the `<form>` element
|
||||
|
||||
+makeExample('forms/ts/src/app/hero-form.component.ts', 'directives')
|
||||
<br>
|
||||
:marked
|
||||
The `NgForm` directive supplements the `form` element with additional features.
|
||||
It collects `Controls` (elements identified by an `ng-control` directive)
|
||||
and monitors their properties including their validity.
|
||||
|
@ -483,11 +495,11 @@ figure.image-display
|
|||
|
||||
In this example, we are pulling the "name" control out of its `controls` collection
|
||||
and assigning it to the template local variable so that we can
|
||||
access the control's properties ... such as the control's own `valid` property.
|
||||
access the control's properties — such as the control's own `valid` property.
|
||||
:marked
|
||||
The "AlterEgo" is optional so we can leave that be.
|
||||
The Hero *Alter Ego* is optional so we can leave that be.
|
||||
|
||||
"Power" selection is required.
|
||||
Hero *Power* selection is required.
|
||||
We can add the same kind of error handling to the `<select>` if we want
|
||||
but it's not imperative because the selection box already constrains the
|
||||
power to valid value.
|
||||
|
@ -496,14 +508,14 @@ figure.image-display
|
|||
:marked
|
||||
## Submit the form with **ng-submit**
|
||||
The user should be able to submit this form after filling it in.
|
||||
The "Submit" button at the bottom of the form
|
||||
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"`).
|
||||
|
||||
A "form submit" is meaningless at the moment.
|
||||
We'll update the `<form>` tag with another Angular directive, `NgSubmit`,
|
||||
To make it meaningful, we'll update the `<form>` tag with another Angular directive, `NgSubmit`,
|
||||
and bind it to our `HeroFormComponent.submit()` method with an EventBinding
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-submit')
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'ng-submit')(format=".")
|
||||
|
||||
:marked
|
||||
We slipped in something extra there at the end! We defined a
|
||||
|
@ -521,10 +533,8 @@ figure.image-display
|
|||
If we run the application now, we find that the button is enabled.
|
||||
It doesn't do anything useful yet but it's alive.
|
||||
|
||||
Now if we delete the "Name", we violate the "required" rule which
|
||||
is duely noted in our error message.
|
||||
|
||||
Check the "Submit" button. It should be disabled.
|
||||
Now if we delete the *Name*, we violate the "required" rule which
|
||||
is duely noted in our error message. The Submit button is also disabled.
|
||||
|
||||
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?
|
||||
|
@ -535,7 +545,7 @@ figure.image-display
|
|||
|
||||
.l-main-section
|
||||
:marked
|
||||
## Toggle two form regions (Extra Credit)
|
||||
## Toggle two form regions (extra credit)
|
||||
Submitting the form isn't terribly dramatic at the moment.
|
||||
.l-sub-section
|
||||
:marked
|
||||
|
@ -543,40 +553,40 @@ figure.image-display
|
|||
jazzing it up won't teach us anything new about forms.
|
||||
But this is an opportunity to exercise some of our newly won
|
||||
binding skills.
|
||||
If we're not interested, we can skip to the chapter's conclusion
|
||||
If you're not interested, you can skip to the chapter's conclusion
|
||||
and not miss a thing.
|
||||
:marked
|
||||
Let's do something more strikingly visual.
|
||||
Let's hide the data entry area and display something else.
|
||||
|
||||
Start by wrapping the form in a `<div>` and binding
|
||||
Start by wrapping the form in a `<div>` and bind
|
||||
its `hidden` property to the `HeroFormComponent.submitted` property.
|
||||
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'edit-div')
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'edit-div', 'app/hero-form.component.html (excerpt)')
|
||||
|
||||
: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:
|
||||
the `submitted` property is false until we submit the form,
|
||||
as this fragment from the `HeroFormComponent` reminds us:
|
||||
|
||||
+makeExample('forms/ts/src/app/hero-form.component.ts', 'submitted')
|
||||
|
||||
:marked
|
||||
When we click the "Submit" button, the `submitted` flag becomes true and the form disappears
|
||||
When we click the Submit button, the `submitted` flag becomes true and the form disappears
|
||||
as planned.
|
||||
|
||||
Now we need to show something else while the form is in the submitted state.
|
||||
Add the following block of HTML below the `<div>` wrapper we just wrote:
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'submitted')
|
||||
+makeExample('forms/ts/src/app/hero-form.component.html', 'submitted', 'app/hero-form.component.html (excerpt)')
|
||||
|
||||
: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.
|
||||
|
||||
There's an "Edit" button whose click event we bound to an expression
|
||||
We added an Edit button whose click event is bound to an expression
|
||||
that clears the `submitted` flag.
|
||||
|
||||
Click it and this block disappears and the editable form reappears.
|
||||
When we click it, this block disappears and the editable form reappears.
|
||||
|
||||
That's as much drama as we can muster for now.
|
||||
|
||||
|
@ -596,7 +606,7 @@ figure.image-display
|
|||
- Property Binding to disable the submit button when the form is invalid.
|
||||
- Custom CSS classes that provide visual feedback to users about required invalid controls.
|
||||
|
||||
Here’s the final version of the application includes all of these framework features:
|
||||
Here’s the final version of the application:
|
||||
|
||||
+makeTabs(
|
||||
`forms/ts/src/app/hero-form.component.html,
|
||||
|
|
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Reference in New Issue