OVERVIEW
Razor components are specific building blocks within the Blazor framework. They can perform many roles: representing a specific piece of the user interface, a view component, or a tag helper; or representing a layout or an entire page. In Razor Components Succinctly, you will explore how to create and work with both simple and advanced Razor components. Longtime Succinctly author Ed Freitas will show you how to write a basic component using one-way data binding and events, and then two-way data binding, event callbacks, life cycle methods, and component references. Finally, you'll see how to enable component reuse by creating a component template.

TABLE OF CONTENTS
Razor Components
Setup and Fundamentals
Component Fundamentals
Component Features
Using Components
Templating

Author
Ed Freitas

ISBN
978-1-64200-211-9

Published on
April 16, 2021

Pages
102 

> ng new my-app

> ng new my-app --dry-run

>ng new my-app --dry-run
installing ng
You specified the dry-run flag, so no changes will be written.
  create .editorconfig
  create README.md
  create src\app\app.component.css
  create src\app\app.component.html
.
.
.
Project 'my-app' successfully created.

> ng new my-app --skip-install

> ng new --help

"project": {
      "name": "my-app"
  },

"apps": [
{
   "root": "src",
   "outDir": "dist",

"prefix": "app",

@Component({
  selector: 'app-root',

> ng new my-project --skip-install --prefix myCompany

> ng new my-project --skip-install --skip-git --skip-tests --skip-commit

"styles": [
     "styles.css"
],

"defaults": {
   "styleExt": "css",
   "component": {}
  }

> ng new my-project --skip-install --style sass

"styles": [
    "styles.sass"
],
"defaults": {
   "styleExt": "sass",
   "component": {}
}

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.sass']
})

> ng new my-project --skip-install --routing

const routes: Routes = [
  {
     path: '',
     children: []
  }
];

imports: [
   BrowserModule,
   FormsModule,
   HttpModule,
   AppRoutingModule
],

>ng serve -o

 http://localhost:4200/

 <h1>
Test
  {{title}}
</h1>

>ng set apps.prefix myCompany
>ng set apps.prefix myCompany -g

>ng set defaults.styleExt sass
>ng set defaults.styleExt sass -g

> ng lint

> ng lint --help

> ng lint --format stylish

>ng lint --fix

import { Component } from '@angular/core'
let number = 10;

>ng lint --format stylish

/src/app/app.component.ts[3, 5]: Identifier 'number' is never reassigned; use 'const' instead of 'let'.
/src/app/app.component.ts[1, 42]: Missing semicolon

Lint errors found in the listed files.

import { Component } from '@angular/core';
const number = 10;

An Angular Roadmap — The Past, Present, and Future of Angular 

Our beginner's guide to building Web APIs with ASP.NET Core is designed to provide you with the foundation you need to start building Web APIs with .NET in a collection of short, pragmatic collection of videos. Web APIs have become a critical component in almost every type of software we use today. In this introductory video series, we will walk you through the fundamental concepts you need to know to get started with building Web APIs using ASP.NET Core. We will cover topics such as routing, validation, working with data, and much more.  

Today is the official GA release for .NET 5, and along with it we are excited to share the latest updates with our recent release of C#/WinRT version 1.0. C#/WinRT provides WinRT projection support for .NET 5 based apps. The Windows SDK leverages this technology and is now integrated with the .NET 5.0 SDK to expose Windows APIs through the new Target Framework Monikers. In addition to the Windows SDK support added for .NET 5, C#/WinRT itself allows component authors to build their own .NET 5 projections using the CsWinRT NuGet package.  

These are the customer-reported issues addressed in 15.9.4:

• Visual Studio 15.9 duplicate loads open files on solution reload.
• All users can now connect to on-premise TFS servers through Team Explorer.
• Visual Studio 15.8.3 no longer expands metadata in ItemDefinitionGroup for project-defined items during GUI builds (worked in Visual Studio 15.8.2).
• Visual Studio has multiple tabs for the same file.
• System.ArgumentException: The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG)).
• LNK4099 PDB not found.
• Asset Catalog empty.
• /analyze fails for C++ code using /ZW.
• C++ compiler code optimization bug.
• Xamarin.iOS can't select image asset for Image View.
• iOS projects referencing a shared project containing image assets in an asset catalog fail to load on windows.
• Image not populating on iOS splashscreen in VS 15.8.6.
• Possible bad codegen on union/bitfield assignment in VS2017 15.8.
• Fix C# UWP Store 1201 Submission Issue.
• Fix C# UWP package creation error APPX1101: Payload contains two or more files with the same destination path 'System.Runtime.CompilerServices.Unsafe.dll'.
• Error MT2002: Failed to resolve 'System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder' reference from 'System.Threading.Tasks.Extensions...'" when building a Xamarin.iOS project.
• Redirecting to a relative url doesn't work when using AndroidClientHandler.
• Debug information for typedefs of unnamed enums compiled with the C compiler is now restored.
• The spectre-mitigated x86 version of delayimp.lib is now built with /Qspectre mitigations enabled.
• Changes were made to how Asset Catalogs in Xamarin.iOS projects are loaded in order to reduce solution load time.
• We have updated Xamarin.Forms templates to use the latest version.
• We have fixed an issue with ASP.NET Core Web Applications being debugged through Kestrel that would show the error message "Unable to configure HTTPS endpoint. No server certificate was specified...".
• Enabling the AppInsights site extension in App Service from Visual Studio now happens through the use of specific Application Settings.

Security Advisory Notices

• An elevation of privilege vulnerability exists when the Diagnostics Hub Standard Collector Service improperly handles certain file operations. 

In this post, let's go through another feature that got introduced to ASP.NET Core in .NET 6 Preview 4. That is Async Streaming. 

 let dialogRef = dialog.open(UserProfileComponent,  { height: '400px’,  width: '600px’  });

dialogRef.afterClosed().subscribe(result => {
   console.log(`Dialog result: ${result}`);
});
dialogRef.close('value');

@Component({/* ... */})
export class YourDialog {

   constructor(public dialogRef: MatDialogRef<YourDialog>) { }

   closeDialog() {
      this.dialogRef.close('Value….!’);
   }
}

<h2 mat-dialog-title>Delete all</h2>
<mat-dialog-content>Are you sure?</mat-dialog-content>
<mat-dialog-actions>
    <button mat-button mat-dialog-close>No</button>
    <!-- Can optionally provide a result for the closing dialog. -->
    <button mat-button [mat-dialog-close]="true">Yes</button>
</mat-dialog-actions>

<mat-toolbar color="primary">
  <button mat-button fxHide fxHide.xs="false" (click)="toggleSidenav.emit()">
    <mat-icon>menu</mat-icon>
  </button>

  <span>Contact Manager</span>

  <span fxFlex="1 1 auto"></span>
  <button mat-button [matMenuTriggerFor]="menu">
    <mat-icon>more_vert</mat-icon>
  </button>
  <mat-menu #menu="matMenu">
    <button mat-menu-item>New Contact</button>
  </mat-menu>
</mat-toolbar>

 <button mat-menu-item (click)="openAddContactDialog()">New Contact</button>

 ng g c contact-manager/components/new-contact-dialog --no-spec

import { NewContactDialogComponent } from "./components/new-contact-dialog/new-contact-dialog.component";

@NgModule({
  declarations: [
    NewContactDialogComponent],
  entryComponents: [
    NewContactDialogComponent
  ]
})
export class ContactManagerModule { }

import { Component, EventEmitter, OnInit, Output } from "@angular/core";
import { MatDialog } from "@angular/material";

import { NewContactDialogComponent } from "../new-contact-dialog/new-contact-dialog.component";

@Component({
  selector: "app-toolbar",
  templateUrl: "./toolbar.component.html",
  styleUrls: ["./toolbar.component.css"]
})
export class ToolbarComponent implements OnInit {

  @Output() toggleSidenav = new EventEmitter<void>();

  constructor(private dialog: MatDialog) { }

  ngOnInit() { }

  openAddContactDialog(): void {
    const dialogRef = this.dialog.open(NewContactDialogComponent, { width: "450px" });
    dialogRef.afterClosed().subscribe(result => {
      console.log("The dialog was closed", result);
    });
  }
}

<h2 mat-dialog-title>Add new contact</h2>
<mat-dialog-content>
  <div fxLayout="column">

  </div>
</mat-dialog-content>
<mat-dialog-actions>
  <button mat-button color="primary" (click)="save()">
    <mat-icon>save</mat-icon> Save
  </button>
  <button mat-button color="primary" (click)="dismiss()">
    <mat-icon>cancel</mat-icon> Cancel
  </button>
</mat-dialog-actions>

import { Component, OnInit } from "@angular/core";
import { MatDialogRef } from "@angular/material";

@Component()
export class NewContactDialogComponent implements OnInit {

  constructor(
    private dialogRef: MatDialogRef<NewContactDialogComponent>
  ) { }

  ngOnInit() {
  }

  save() {
  }

  dismiss() {
    this.dialogRef.close(null);
  }
}

import { User } from "../../models/user";

@Component()
export class NewContactDialogComponent implements OnInit {

  avatars = ["user1", "user2", "user3", "user4", "user5", "user6", "user7", "user8"];
  user: User = { id: 0, birthDate: new Date(), name: "", avatar: "", bio: "", userNotes: null };

    <mat-form-field>
      <mat-select placeholder="Avatar" [(ngModel)]="user.avatar">
        <mat-select-trigger>
          <mat-icon svgIcon="{{user.avatar}}"></mat-icon> {{ user.avatar }}
        </mat-select-trigger>
        <mat-option *ngFor="let avatar of avatars" [value]="avatar">
          <mat-icon svgIcon="{{avatar}}"></mat-icon> {{ avatar }}
        </mat-option>
      </mat-select>
    </mat-form-field>

    <mat-form-field>
      <input matInput placeholder="Name" #name="ngModel" [(ngModel)]="user.name" required>
      <mat-error *ngIf="name.invalid && name.touched">You must enter a name</mat-error>
    </mat-form-field>

    <mat-form-field>
      <input matInput [matDatepicker]="picker" placeholder="Born" [(ngModel)]="user.birthDate">
      <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
      <mat-datepicker #picker></mat-datepicker>
    </mat-form-field>

    <mat-form-field>
      <textarea matInput placeholder="Bio" [(ngModel)]="user.bio"></textarea>
    </mat-form-field>

<mat-dialog-content>
  <div fxLayout="column">

  </div>
</mat-dialog-content>

namespace MaterialAspNetCoreBackend.WebApp.Controllers
{
    [Route("api/[controller]")]
    public class UsersController : Controller
    {
        private readonly IUsersService _usersService;

        public UsersController(IUsersService usersService)
        {
            _usersService = usersService ?? throw new ArgumentNullException(nameof(usersService));
        }

        [HttpPost]
        public async Task<IActionResult> Post([FromBody] User user)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            await _usersService.AddUserAsync(user);
            return Created("", user);
        }
    }
}

@Injectable({
  providedIn: "root"
})
export class UserService {

  private usersSource = new BehaviorSubject<User>(null);
  usersSourceChanges$ = this.usersSource.asObservable();

  constructor(private http: HttpClient) { }

  addUser(user: User): Observable<User> {
    const headers = new HttpHeaders({ "Content-Type": "application/json" });
    return this.http
      .post<User>("/api/users", user, { headers: headers }).pipe(
        map(response => {
          const addedUser = response || {} as User;
          this.notifyUsersSourceHasChanged(addedUser);
          return addedUser;
        }),
        catchError((error: HttpErrorResponse) => throwError(error))
      );
  }

  notifyUsersSourceHasChanged(user: User) {
    this.usersSource.next(user);
  }
}

 return Created("", user);

import { UserService } from "../../services/user.service";

@Component()
export class NewContactDialogComponent {

  user: User = { id: 0, birthDate: new Date(), name: "", avatar: "", bio: "", userNotes: null };

  constructor(
    private dialogRef: MatDialogRef<NewContactDialogComponent>,
    private userService: UserService
  ) { }

  save() {
    this.userService.addUser(this.user).subscribe(data => {
      console.log("Saved user", data);
      this.dialogRef.close(data);
    });
  }
}

import { UserService } from "../../services/user.service";

@Component()
export class SidenavComponent implements OnInit, OnDestroy {

  users: User[] = [];
  subscription: Subscription | null = null;

  constructor(
    private userService: UserService) { }

  ngOnInit() {
    this.subscription = this.userService.usersSourceChanges$.subscribe(user => {
      if (user) {
        this.users.push(user);
      }
    });
  }

  ngOnDestroy() {
    if (this.subscription) {
      this.subscription.unsubscribe();
    }
  }
}

  save() {
    this.userService.addUser(this.user).subscribe(data => {
      console.log("Saved user", data);
      this.dialogRef.close(data);
    });

  openAddContactDialog(): void {
    const dialogRef = this.dialog.open(NewContactDialogComponent, { width: "450px" });
    dialogRef.afterClosed().subscribe(result => {
      console.log("The dialog was closed", result);
    });
  }

@Component()
export class ToolbarComponent {

  @Output() toggleSidenav = new EventEmitter<void>();

  constructor(private dialog: MatDialog, private snackBar: MatSnackBar,  private router: Router) { }

  openAddContactDialog(): void {
    const dialogRef = this.dialog.open(NewContactDialogComponent, { width: "450px" });
    dialogRef.afterClosed().subscribe((result: User) => {
      console.log("The dialog was closed", result);
      if (result) {
        this.openSnackBar(`${result.name} contact has been added.`, "Navigate").onAction().subscribe(() => {
          this.router.navigate(["/contactmanager", result.id]);
        });
      }
    });
  }

  openSnackBar(message: string, action: string): MatSnackBarRef<SimpleSnackBar> {
    return this.snackBar.open(message, action, {
      duration: 5000,
    });
  }
}