ASP.NET Core

Last week’s post covered adding a read-only view of a contact’s details. As before the goal is to get the React project’s features in line with the Aurelia and Angular samples. This week we will be adding a form to all addition of a new contact. The code before any changes can be found here.

Contact List

On the contact list page, we need to add a link to create a contact. This will be added just after the header in the ContactList.tsx file.

<h1>Contact List</h1>
<Link to={'contactdetail'}>Create New Contact</Link>

Routing

In order to stay in line with the other sample, the ContactDetail component is going to be handling both the read-only view and the view to add a contact. This means the ID that is currently part of the contact detail needs to be optional. The following is the change to make ID optional by adding a question mark.

Before:
<Route path='/contactdetail/:id' component={ContactDetail} />

After:
<Route path='/contactdetail/:id?' component={ContactDetail} />

Contact Service

In the ContactService class, we need to add a save function. This new function will make a post request to the contacts API and return the new contact with the ID from the API to the caller.

save(contact: Contact): Promise<Contact> {
    return fetch(this.baseUrl,
            {
                method: 'post',
                headers: {
                    'Accept': 'application/json',
                    'Content-Type': 'application/json' 
                },
                body: JSON.stringify(contact)
            })
        .then(response => response.json())
        .then(contact => new Contact(contact));
}

Contact Detail

The ContactDetail class is where most of the changes are. I had some trouble getting React’s forms to work directly with the instance of the contact class and ended up just storing the parts of a contact directly in state instead of as an object. I expect this is a failure on my part and not an issue with React. I may revisit this in the future. Below is the new structure of the state used by contact details.

interface ContactDetailState {
    id: string;
    name: string;
    address: string;
    city: string;
    state: string;
    postalCode: string;
    phone: string;
    email: string;
    loading: boolean;
    redirect: boolean;
}

Next, the constructor needed to be changed to handle the new state structure and to handle being called without an ID.

constructor(props: any) {
    super();

    if (props.match.params.id == undefined) {
        this.state = {
            id: props.match.params.id,
            name: '', address: '', city: '',
            state: '', postalCode: '', phone: '',
            email: '',
            loading: false,
            redirect: false
        };
    }
    else {
        this.state = {
            id: props.match.params.id,
            name: '', address: '', city: '',
            state: '', postalCode: '', phone: '',
            email: '',
            loading: true,
            redirect: false
        };

        let contactService = new ContactService();
        contactService.getById(this.state.id)
            .then(data => {
                this.setState({
                    name: data.name, address: data.address, city: data.city,
                    state: data.state, postalCode: data.postalCode, phone: data.phone,
                    email: data.email,
                    loading: false
                });
            });
    }
}

Again, this is way more code than it would be the contact class were being used. Next, the render function needs to be adjusted to render the UI for the read-only view or the contact creation. The decision is based on the ID being set or undefined.

public render() {
    let contents = this.state.loading
        ? <p><em>Loading...</em></p>
        : this.state.id != undefined &&
          !this.state.redirect
            ? this.renderExistingContact()
            : this.renderNewContact();

    return <div>
        <h1>Contact Detail</h1>
        <hr />
        {contents}
        <NavLink to={'/contactlist'}>Back to List</NavLink>
        <hr />
    </div>;
}

The render of an existing contact needs to be changed to use state instead of an instance of a contact.

private renderExistingContact() {
    return <dl className="dl-horizontal">
        <dt>ID</dt>
        <dd>{this.state.id}</dd>
        <dt>Name</dt>
        <dd>{this.state.name}</dd>
        <dt>Address</dt>
        <dd>{this.state.address} {this.state.city}, {this.state.state} {this.state.postalCode}</dd>
        <dt>Phone</dt>
        <dd>{this.state.phone}</dd>
        <dt>Email</dt>
        <dd>{this.state.email}</dd>
    </dl>;
}

The following is the render of the add contact UI. I will call out a couple of parts after. The bulk of the code is just rending of the form.

    private renderNewContact() {
        return (
            <div>
                {this.state.redirect && <Redirect to={`/contactdetail/${this.state.id}`}/>}
                <form role="form" className="form-horizontal" onSubmit={(e: any) => this.handleSubmit(e)}>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">Name</label>
                        <div className="col-sm-10">
                            <input type="text" placeholder="name" className="form-control" name="name" value={this.state.name} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">Address</label>
                        <div className="col-sm-10">
                            <input type="text" placeholder="address" className="form-control" name="address" value={this.state.address} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">City</label>
                        <div className="col-sm-10">
                            <input type="text" placeholder="city" className="form-control" name="city" value={this.state.city} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">State</label>
                        <div className="col-sm-10">
                            <input type="text" placeholder="state" className="form-control" name="state" value={this.state.state} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">Zip</label>
                        <div className="col-sm-10">
                            <input type="text" placeholder="zip" className="form-control" name="postalCode" value={this.state.postalCode} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">Phone</label>
                        <div className="col-sm-10">
                            <input type="text" placeholder="phone" className="form-control" name="phone" value={this.state.phone} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="form-group">
                        <label className="col-sm-2 control-label">Email</label>
                        <div className="col-sm-10">
                            <input type="email" placeholder="email" className="form-control" name="email" value={this.state.email} onChange={(e: any) => this.handleChange(e)} />
                        </div>
                    </div>
                    <div className="text-center">
                        <button className="btn btn-success btn-lg" type="submit">Save</button>
                        <button className="btn btn-danger btn-lg" onClick={() => this.reset()}>Reset</button>
                    </div >
                </form>
            </div>
        );
    }

The following is the input for the contact’s name.

<input type="text" placeholder="name" className="form-control" name="name" value={this.state.name} onChange={(e: any) => this.handleChange(e)} />

Since I decided to go with the controlled component route React will be responsible for being the source of truth, not the form its self. To accomplish this it is important that the input has a name and an onChange event handler set up. The following is the handleChange function which uses the name from the on change event to update the proper property in the component’s state.

private handleChange(event: any): void {
    const target = event.target;
    const value = target.value;
    const name = target.name;

    this.setState({ [name]: value });
}

The following line is the reset button which will reset the state to blank out all the fields in the form.

<button className=”btn btn-danger btn-lg” onClick={() => this.reset()}>Reset</button>

The reset function just uses setState to blank out all the fields.

private reset() {
    this.setState({
        name: '', address: '', city: '',
        state: '', postalCode: '', phone: '',
        email: ''
    });
}

Not surprisingly the submit button triggers a submit of the form. What happens on submit is defined in the opening form tag.

<form role="form" className="form-horizontal" onSubmit={(e: any) => this.handleSubmit(e)}>

The handleSubmit function takes the contact information in state and uses it to create a new instance of a Contact which is then passed to the ContactService to be saved. The service returns a new contact object from the server and the ID is stored to state.

handleSubmit(event: any): void {
    event.preventDefault();

    let contact = new Contact();
    contact.name = this.state.name;
    contact.address = this.state.address;
    contact.city = this.state.city;
    contact.state = this.state.state;
    contact.postalCode = this.state.postalCode;
    contact.phone = this.state.phone;
    contact.email = this.state.email;

    let contactService = new ContactService();
    contactService.save(contact)
        .then(c => this.setState({ id: String(c.id) }));

    if (this.state.id) {
        this.setState({ redirect: true });
    }
}

If the server does return an ID for the new contact then the redirect is set to true. Then will case the following code to run in renderNewContact which will redirect the user back to the read-only view of the new contact.

{this.state.redirect && <Redirect to={`/contactdetail/${this.state.id}`}/>}

Wrapping Up

This pretty much gets the React application in line with the Aurelia and Angular sample applications. It has been fun getting a handle on the very, very basics of React. While I am back in the basics sample projects I may go ahead and tackle a Vue sample next.

The finished code can be found here.

Last week’s post covered adding a React project to the ASP.NET Core Basics solution. As I stated last week the goal is to get the React project’s features in line with the Aurelia and Angular samples. This week we will be adding a read-only view of a contact’s details. The code before any changes can be found here.

Contact Class

The Contact interface in the ContactList.tsx should be deleted and in its please we will add a Contact class. As part of this change, I also moved the contact related items to a contact directory. Add a contact.ts file to the ClientApp/components/contacts/ directory with the following contents.

export class Contact {
    id: number;
    name: string;
    address: string;
    city: string;
    state: string;
    postalCode: string;
    phone: string;
    email: string;

    constructor(data?: any) {
        if (data == null) return;
        (<any>Object).assign(this, data);
    }

    getAddress(): string {
        return `${this.address} ${this.city}, ${this.state} ${this.postalCode}`;
    }

}

This class is very simple and will be used later to show how a function call can be used as part of rendering.

Contact Service

Since the application will now have two places that need to access the ASP.NET Core API I decided to refactor the API access behind a service. This is the same style used by the Aurelia and Angular applications. Add a contactService.ts file to the Contacts directory. The service will provide functions to get all contacts or a single contact using its ID. The following is the full class.

import 'isomorphic-fetch';
import { Contact } from './contact';

export class ContactService {

    private baseUrl = 'http://localhost:13322/api/contactsApi/';

    getAll(): Promise<Contact[]> {
        return fetch(this.baseUrl)
            .then(response => response.json() as Promise<Contact[]>)
            .then(contacts => Array.from(contacts, c => new Contact(c)));
    }

    getById(id: string): Promise<Contact> {
        return fetch(`${this.baseUrl}${id}`)
            .then(response => response.json())
            .then(contact => new Contact(contact));
    }

}

The final step in this refactor is to use the new service in the ContactList class. First, add imports for the service and Contact class.

import { Contact } from './contact';
import { ContactService } from './contactService';

Then, replace the fetch call with the service.

Before:
fetch('http://localhost:13322/api/contactsApi/')
    .then(response => response.json() as Promise<Contact[]>)

After:
let contactService = new ContactService();
contactService.getAll()

Contact Detail Component

Add a ContactDetail.tsx file which will be used to show the details of a contact including using the getAddress function of the Contact class. The following is the full contents of the file.

import * as React from 'react';
import { RouteComponentProps } from 'react-router';
import { Link, NavLink } from 'react-router-dom';
import 'isomorphic-fetch';
import { Contact } from './contact';
import { ContactService } from './contactService';

interface ContactDetailState {
    id: string;
    contact: Contact | undefined;
    loading: boolean;
}

export class ContactDetail extends React.Component<RouteComponentProps<{}>, ContactDetailState> {

    constructor(props: any) {
        super();
        this.state = { id: props.match.params.id, contact: undefined, loading: true };

        let contactService = new ContactService();
        contactService.getById(this.state.id)
            .then(data => {
                this.setState({ contact: data, loading: false });
            });
    }

    public render() {
        let contents = this.state.loading
            ? <p><em>Loading...</em></p>
            : this.state.contact
                ? ContactDetail.renderContactsTable(this.state.contact)
                : <p>No contacts</p>;

        return <div>
            <h1>Contact Detail</h1>
            <hr />
            {contents}
            <NavLink to={'/contactlist'}>Back to List</NavLink>
            <hr />
        </div>;
    }

    private static renderContactsTable(contact: Contact) {
        return <dl className="dl-horizontal">
                   <dt>ID</dt>
                   <dd>{contact.id}</dd>
                   <dt>Name</dt>
                   <dd>{contact.name}</dd>
                   <dt>Address</dt>
                   <dd>{contact.getAddress()}</dd>
                   <dt>Phone</dt>
                   <dd>{contact.phone}</dd>
                   <dt>Email</dt>
                   <dd>{contact.email}</dd>
               </dl>;
    }
}

This is all very similar to the things I have covered before. Now that we have a contact detail component we need a way to display it.

Routing with a Parameter

Import the contact detail in the route.tsx file.

import { ContactDetail } from './components/contacts/ContactDetail';

Next, add a route path for contact detail that expects an ID.

<Route path='/contactdetail/:id' component={ContactDetail} />

Back in the ContactList component change the ID to be a link to the new contact detail route using the ID of the contact.

Before:
<td>{contact.id}</td>

After:
<td><Link to={`contactdetail/${contact.id}`}>{contact.id}</Link></td>

The code for pulling the route parameter was in the ContactDetail component above, but I am going to show it again just so all the route with parameter information is together. The route parameters can be accessed using props.match.params.{parameter name} which in this case ends up being props.match.params.id. The following is the constructor of the ContactDetail component which is using a route parameter.

constructor(props: any) {
    super();
    this.state = { id: props.match.params.id, contact: undefined, loading: true };

    let contactService = new ContactService();
    contactService.getById(this.state.id)
        .then(data => {
            this.setState({ contact: data, loading: false });
        });
}

Wrapping Up

This brings the projects one step closer to being on the same level feature-wise. I expect at least one more post to get the project features lined up so make sure and keep a lookout for the next post.

Keep in mind that this is my first look at React and my examples may or may not be idiomatic. So far I am really enjoying working with React.

The code in a finished state can be found here.