>ng g s employee/FormPoster -m employee.module

 installing service
  create src\app\employee\form-poster.service.spec.ts
  create src\app\employee\form-poster.service.ts
  update src\app\employee\employee.module.ts

import { Injectable } from '@angular/core';
import { Http } from '@angular/http';

import { Employee } from './employee';

@Injectable()
export class FormPosterService {

    constructor(private http:Http) {
    }

    postEmployeeForm(employee: Employee) {
    }
}

import { HttpModule } from "@angular/http";

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    EmployeeModule,
    AppRoutingModule
  ]

import { FormPosterService } from "../form-poster.service";

export class EmployeeRegisterComponent implements OnInit {

  constructor(private formPoster: FormPosterService) {}

}

>npm install
>ng build --watch

>dotnet restore
>dotnet watch run

<form #form="ngForm" (submit)="submitForm(form)" novalidate>

export class EmployeeRegisterComponent implements OnInit {
  submitForm(form: NgForm) {
    console.log(this.model);
    console.log(form.value);
  }
}

import { Injectable } from "@angular/core";
import { Http, Response, Headers, RequestOptions } from "@angular/http";

import { Observable } from "rxjs/Observable";
import "rxjs/add/operator/do";
import "rxjs/add/operator/catch";
import "rxjs/add/observable/throw";
import "rxjs/add/operator/map";
import "rxjs/add/observable/of";

import { Employee } from "./employee";

@Injectable()
export class FormPosterService {
  private baseUrl = "api/employee";

  constructor(private http: Http) {}

  private extractData(res: Response) {
    const body = res.json();
    return body.fields || {};
  }

  private handleError(error: Response): Observable<any> {
    console.error("observable error: ", error);
    return Observable.throw(error.statusText);
  }

  postEmployeeForm(employee: Employee): Observable<Employee> {
    const body = JSON.stringify(employee);
    const headers = new Headers({ "Content-Type": "application/json" });
    const options = new RequestOptions({ headers: headers });

    return this.http
      .post(this.baseUrl, body, options)
      .map(this.extractData)
      .catch(this.handleError);
  }
}

  submitForm(form: NgForm) {
    console.log(this.model);
    console.log(form.value);

    // validate form
    this.validatePrimaryLanguage(this.model.primaryLanguage);
    if (this.hasPrimaryLanguageError) {
      return;
    }

    this.formPoster
      .postEmployeeForm(this.model)
      .subscribe(
        data => console.log("success: ", data),
        err => console.log("error: ", err)
      );
  }

export class FormPosterService {
  private baseUrl = "api/employee";

namespace AngularTemplateDrivenFormsLab.Models
{
    public class Employee
    {
        public int Id { set; get; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public bool IsFullTime { get; set; }
        public string PaymentType { get; set; }
        public string PrimaryLanguage { get; set; }
    }
}

using Microsoft.AspNetCore.Mvc;
using AngularTemplateDrivenFormsLab.Models;

namespace AngularTemplateDrivenFormsLab.Controllers
{
    [Route("api/[controller]")]
    public class EmployeeController : Controller
    {
        public IActionResult Post([FromBody] Employee model)
        {
            //todo: save model

            model.Id = 100;
            return Created("", new { fields = model });
        }
    }
}

{"fields":{"id":100,"firstName":"Vahid","lastName":"N","isFullTime":true,"paymentType":"FullTime","primaryLanguage":"Persian"}}

  private extractData(res: Response) {
    const body = res.json();
    return body.fields || {};
  }

 data => console.log("success: ", data)

[HttpGet("/api/[controller]/[action]")]
public IActionResult Languages()
{
    string[] languages = { "Persian", "English", "Spanish", "Other" };
    return Ok(languages);
}

  private extractLanguages(res: Response) {
    const body = res.json();
    return body || {};
  }

  getLanguages(): Observable<any> {
    return this.http
      .get(`${this.baseUrl}/languages`)
      .map(this.extractLanguages)
      .catch(this.handleError);
  }

  languages = [];

  ngOnInit() {
    this.formPoster
      .getLanguages()
      .subscribe(
        data => this.languages = data,
        err => console.log("get error: ", err)
      );
  }

<h3 *ngIf="languages.length == 0">Loading...</h3>
<div class="container" *ngIf="languages.length > 0">

>npm install
>ng build --watch

>dotnet restore
>dotnet watch run

App.controller('parentController', ['$rootScope', '$scope', 'authService', 'permissionService', function ($rootScope, $scope, authService, permissionService) {
        $scope.authentication = authService.authentication;

        // isAuthorize Method
        $scope.isAuthorize = permissionService.isAuthorize();

        // rest of codes
}]);

services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(connectionString));

public static IServiceCollection AddDbContext<TContext>(
    [NotNullAttribute] this IServiceCollection serviceCollection, 
    [CanBeNullAttribute] Action<DbContextOptionsBuilder> optionsAction = null, 
    ServiceLifetime contextLifetime = ServiceLifetime.Scoped, 
    ServiceLifetime optionsLifetime = ServiceLifetime.Scoped) where TContext : DbContext;

 An exception occurred while iterating over the results of a query for context type 'BlazorServer.DataAccess.ApplicationDbContext'.
System.InvalidOperationException: A second operation was started on this context before a previous operation completed.
This is usually caused by different threads concurrently using the same instance of DbContext.
For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.

public void ConfigureServices(IServiceCollection services)
{
    var connectionString = Configuration.GetConnectionString("DefaultConnection");
    //services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(connectionString));
    services.AddDbContextFactory<ApplicationDbContext>(options => options.UseSqlServer(connectionString));

@inject IDbContextFactory<ApplicationDbContext> DbFactory

private async Task DeleteImageAsync()
{
    using var context = DbFactory.CreateDbContext();

    var image = await context.HotelRoomImages.FindAsync(1);

   // ...
}

@implements IDisposable
@inject IDbContextFactory<ApplicationDbContext> DbFactory


@code
{
   private ApplicationDbContext Context;

   protected override async Task OnInitializedAsync()
   {
       Context = DbFactory.CreateDbContext();
       await base.OnInitializedAsync();
   }

   private async Task DeleteImageAsync()
   {
       var image = await Context.HotelRoomImages.FindAsync(1);
       // ...
   }

   public void Dispose()
   {
     Context.Dispose();
   }
}

services.AddScoped<ApplicationDbContext>(serviceProvider =>
     serviceProvider.GetRequiredService<IDbContextFactory<ApplicationDbContext>>().CreateDbContext());

public interface IHotelRoomService : IDisposable
{
   // ...
}

public interface IHotelRoomImageService : IDisposable
{
   // ...
}

    public class HotelRoomService : IHotelRoomService
    {
        private bool _isDisposed;

        // ...

        public void Dispose()
        {
            Dispose(disposing: true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!_isDisposed)
            {
                try
                {
                    if (disposing)
                    {
                        _dbContext.Dispose();
                    }
                }
                finally
                {
                    _isDisposed = true;
                }
            }
        }
    }

@page "/hotel-room/create"
@page "/hotel-room/edit/{Id:int}"

@implements IDisposable
// ...


@code
{
    // ...

    public void Dispose()
    {
        HotelRoomImageService.Dispose();
        HotelRoomService.Dispose();
    }
}

@page "/hotel-room"

@implements IDisposable
// ...


@code
{
    // ...

    public void Dispose()
    {
        HotelRoomService.Dispose();
    }
}

System.ObjectDisposedException: Cannot access a disposed context instance.
A common cause of this error is disposing a context instance that was resolved from dependency injection and then
later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose'
on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the
dependency injection container take care of disposing context instances.
Object name: 'ApplicationDbContext'.

@code
{
   private IHotelRoomImageService HotelRoomImageService;

   protected override async Task OnInitializedAsync()
   {
       HotelRoomImageService =  new HotelRoomImageService(DbFactory.CreateDbContext(), mapper);
       await base.OnInitializedAsync();
   }

   private async Task DeleteImageAsync()
   {
       await HotelRoomImageService.DeleteAsync(1);
       // ...
   }

   public void Dispose()
   {
     HotelRoomImageService.Dispose();
   }
}

@page "/hotel-room"

@*@implements IDisposable*@
@*@inject IHotelRoomService HotelRoomService*@
@inherits OwningComponentBase<IHotelRoomService>

@code
{
   private IHotelRoomService HotelRoomService => Service;

@page "/preferences"
@using Microsoft.Extensions.DependencyInjection
@inherits OwningComponentBase


@code {
    private IHotelRoomService HotelRoomService { get; set; }
    private IHotelRoomImageService HotelRoomImageService { get; set; }

    protected override void OnInitialized()
    {
        HotelRoomService = ScopedServices.GetRequiredService<IHotelRoomService>();
        HotelRoomImageService = ScopedServices.GetRequiredService<IHotelRoomImageService>();
    }
}

services.AddDbContextFactory<ApplicationDbContext>(options => options.UseSqlServer(connectionString));
services.AddScoped<ApplicationDbContext>(serviceProvider =>
        serviceProvider.GetRequiredService<IDbContextFactory<ApplicationDbContext>>().CreateDbContext());

@inject IHotelRoomService HotelRoomService

@inherits OwningComponentBase<IHotelRoomService>

With the recent release1.3.14 instantaneous-browserification, Angular introduced better support for those using Browserify. Thank you to everyone who worked onthat issue, and especially toBen Clinkinbeardfor his unflagging dedication in getting it in. 

npm install -g rxjs-tslint
rxjs-5-to-6-migrate -p src/tsconfig.app.json

npm install npm-check-updates -g
ncu -u
npm install

 Application: DNTProfiler.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Windows.Markup.XamlParseException
Stack:
at System.Windows.Markup.WpfXamlLoader.Load

 CommandLine: C:\Tests\DNTProfiler.1.0.808.0\DNTProfiler.exe
Symbol search path is: srv*
Executable search path is:
ModLoad: 00150000 00176000 DNTProfiler.exe
ModLoad: 76f30000 77098000 ntdll.dll
ModLoad: 72ee0000 72f36000 C:\Windows\SysWOW64\MSCOREE.DLL
ModLoad: 74be0000 74d20000 C:\Windows\SysWOW64\KERNEL32.dll
ModLoad: 756e0000 757af000 C:\Windows\SysWOW64\KERNELBASE.dll
(684.764): Break instruction exception - code 80000003 (first chance)
eax=00000000 ebx=00000000 ecx=37af0000 edx=00000000 esi=7eb8f000 edi=00000000
eip=76fe2d15 esp=002ff604 ebp=002ff630 iopl=0 nv up ei pl zr na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b efl=00000246
*** ERROR: Symbol file could not be found.  Defaulted to export symbols for ntdll.dll -
ntdll!LdrResolveDelayLoadsFromDll+0xa89:
76fe2d15 cc   int   3

 0:000> g
ModLoad: 757b0000 75827000 C:\Windows\SysWOW64\ADVAPI32.dll
ModLoad: 05080000 05102000 Newtonsoft.Json.dll
(684.764): C++ EH exception - code e06d7363 (first chance)
(684.764): C++ EH exception - code e06d7363 (first chance)
(684.764): C++ EH exception - code e06d7363 (first chance)
(684.764): CLR exception - code e0434352 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=002fd0a0 ebx=00000005 ecx=00000005 edx=00000000 esi=002fd164 edi=00000001
eip=756f3d67 esp=002fd0a0 ebp=002fd0f8 iopl=0 nv up ei pl nz ac pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b efl=00200216
*** ERROR: Symbol file could not be found.  Defaulted to export symbols for C:\Windows\SysWOW64\KERNELBASE.dll -
KERNELBASE!RaiseException+0x48:
756f3d67 8b4c2454   mov   ecx,dword ptr [esp+54h] ss:002b:002fd0f4=3fce1188

 0:000> sxe clr
0:000> g
(684.764): C++ EH exception - code e06d7363 (first chance)
(684.764): CLR exception - code e0434352 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=002fe2a0 ebx=00000005 ecx=00000005 edx=00000000 esi=002fe368 edi=00000001
eip=756f3d67 esp=002fe2a0 ebp=002fe2fc iopl=0 nv up ei pl nz ac pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b efl=00200216
KERNELBASE!RaiseException+0x48:
756f3d67 8b4c2454   mov   ecx,dword ptr [esp+54h] ss:002b:002fe2f4=3fce2388

 0:000> !loadby sos clr
0:000> !CLRStack
*** ERROR: Symbol file could not be found.  Defaulted to export symbols for C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll -
PDB symbol for clr.dll not loaded
OS Thread Id: 0x764 (0)
Child SP IP Call Site
002fe3f4 756f3d67 [GCFrame: 002fe3f4]
002fe430 756f3d67 [GCFrame: 002fe430]
002fe528 756f3d67 [GCFrame: 002fe528]
002fe544 756f3d67 [HelperMethodFrame_2OBJ: 002fe544] System.RuntimeTypeHandle.CreateInstance(System.RuntimeType, Boolean, Boolean, Boolean ByRef, System.RuntimeMethodHandleInternal ByRef, Boolean ByRef)
DNTProfiler.App.Main()
002ff190 720e2652 [GCFrame: 002ff190]

 0:000> !PrintException
Exception object: 021e6f0c
Exception type: System.Reflection.TargetInvocationException
Message: Exception has been thrown by the target of an invocation.
InnerException: System.IO.FileNotFoundException, Use !PrintException 021e6950 to see more.
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 80131604
0:000> !PrintException 021e6950
Exception object: 021e6950
Exception type: System.IO.FileNotFoundException
Message: Could not load file or assembly 'System.Net.Http.Formatting, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
InnerException: <none>
StackTrace (generated):
SP IP Function
00000000 00000001 DNTProfiler!DNTProfiler.Services.SelfHostConfig.getHostConfiguration(System.String, Boolean)+0x2
002FE298 006B4E54 DNTProfiler!DNTProfiler.Services.SelfHostConfig.OpenWait(System.String, Boolean)+0x14
002FE2B0 006B4A3F DNTProfiler!DNTProfiler.ViewModels.MainWindowViewModel.doStart(System.String)+0x1f
002FE2C0 006B368D DNTProfiler!DNTProfiler.ViewModels.MainWindowViewModel..ctor(DNTProfiler.Common.Mvvm.ICommonDialogsService, DNTProfiler.Common.Controls.DialogManagement.Contracts.IDialogManager)+0xcd
002FE2D8 006B04C9 DNTProfiler!DNTProfiler.MainWindow..ctor()+0x91

StackTraceString: <none>
HResult: 80070002

 0:000> g
0:000> sxe clr
0:000> g
0:000> !loadby sos clr
0:000> !CLRStack
0:000> !PrintException