namespace PdfReportSamples.Models
{
    public class Task
    {
        public int Id { set; get; }
        public string Name { set; get; }
        public int PercentCompleted { set; get; }
        public bool IsActive { set; get; }
    }
}

using System;
using System.Collections.Generic;
using System.Drawing;
using iTextSharp.text;
using PdfReportSamples.Models;
using PdfRpt;
using PdfRpt.Core.Contracts;
using PdfRpt.Core.Helper;
using PdfRpt.FluentInterface;

namespace PdfReportSamples.ProgressReport
{
    public class ProgressReportPdfReport
    {
        private IPdfFont getWatermarkFont()
        {
            var watermarkFont = new GenericFontProvider(
                                        AppPath.ApplicationPath + "\\fonts\\irsans.ttf",
                                        Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts\\verdana.ttf");
            watermarkFont.Color = BaseColor.LIGHT_GRAY;
            watermarkFont.Size = 50;
            return watermarkFont;
        }

        public IPdfReportData CreatePdfReport()
        {
            return new PdfReport().DocumentPreferences(doc =>
            {
                doc.RunDirection(PdfRunDirection.RightToLeft);
                doc.Orientation(PageOrientation.Portrait);
                doc.PageSize(PdfPageSize.A4);
                doc.DocumentMetadata(new DocumentMetadata { Author = "Vahid", Application = "PdfRpt", Keywords = "Test", Subject = "Test Rpt", Title = "Test" });
                doc.DiagonalWatermark(new DiagonalWatermark
                {
                    Text = "نمایش درصد پیشرفت",
                    RunDirection = PdfRunDirection.RightToLeft,
                    Font = getWatermarkFont()
                });
            })
            .DefaultFonts(fonts =>
            {
                fonts.Path(AppPath.ApplicationPath + "\\fonts\\irsans.ttf",
                                  Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts\\verdana.ttf");
            })
            .PagesFooter(footer =>
            {
                footer.DefaultFooter(PersianDate.ToPersianDateTime(DateTime.Now, "/", true));
            })
            .PagesHeader(header =>
            {
                header.DefaultHeader(defaultHeader =>
                {
                    defaultHeader.Message("گزارش جدید ما");
                    defaultHeader.ImagePath(AppPath.ApplicationPath + "\\Images\\01.png");
                });
            })
            .MainTableTemplate(template =>
            {
                template.BasicTemplate(BasicTemplate.SilverTemplate);
            })
            .MainTablePreferences(table =>
            {
                table.ColumnsWidthsType(TableColumnWidthType.Relative);
                table.MultipleColumnsPerPage(new MultipleColumnsPerPage
                {
                    ColumnsGap = 20,
                    ColumnsPerPage = 2,
                    ColumnsWidth = 250,
                    IsRightToLeft = true,
                    TopMargin = 7
                });
            })
            .MainTableDataSource(dataSource =>
            {
                var listOfRows = new List<Task>();
                var rnd = new Random();
                for (int i = 0; i < 400; i++)
                {
                    listOfRows.Add(new Task
                    {
                        Id = rnd.Next(1000, 10000),
                        Name = "Task" + i,
                        PercentCompleted = rnd.Next(1, 100),
                        IsActive = rnd.Next(0, 2) == 1 ? true : false
                    });
                }
                dataSource.StronglyTypedList<Task>(listOfRows);
            })
            .MainTableColumns(columns =>
            {
                columns.AddColumn(column =>
                {
                    column.PropertyName("rowNo");
                    column.IsRowNumber(true);
                    column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                    column.IsVisible(true);
                    column.Order(0);
                    column.Width(1);
                    column.HeaderCell("ردیف", captionRotation: 90);
                });

                columns.AddColumn(column =>
                {
                    column.PropertyName<Task>(x => x.Id);
                    column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                    column.IsVisible(true);
                    column.Order(1);
                    column.Width(2);
                    column.HeaderCell("شماره فعالیت");
                });

                columns.AddColumn(column =>
                {
                    column.PropertyName<Task>(x => x.Name);
                    column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                    column.IsVisible(true);
                    column.Order(2);
                    column.Width(3);
                    column.HeaderCell("فعالیت");
                });

                columns.AddColumn(column =>
                {
                    column.PropertyName<Task>(x => x.PercentCompleted);
                    column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                    column.IsVisible(true);
                    column.Order(3);
                    column.Width(3);
                    column.HeaderCell("درصد پیشرفت");
                    column.ColumnItemsTemplate(template =>
                    {
                        template.ProgressBar(progressBarColor: Color.SkyBlue, showPercentText: true);
                        template.DisplayFormatFormula(obj =>
                        {
                            if (obj == null) return "% 0";
                            return "% " + obj.ToString();
                        });
                    });
                });

                columns.AddColumn(column =>
                {
                    column.PropertyName<Task>(x => x.IsActive);
                    column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                    column.IsVisible(true);
                    column.Order(4);
                    column.Width(2);
                    column.HeaderCell("در جریان");
                    column.ColumnItemsTemplate(template =>
                    {
                        template.Checkmark(checkmarkFillColor: Color.Green, crossSignFillColor: Color.DarkRed);
                    });
                });
            })
            .MainTableEvents(events =>
            {
                events.DataSourceIsEmpty(message: "There is no data available to display.");
            })
            .Export(export =>
            {
                export.ToExcel();
            })
            .Generate(data => data.AsPdfFile(AppPath.ApplicationPath + "\\Pdf\\ProgressReportSample.pdf"));
        }
    }
}

doc.DiagonalWatermark(new DiagonalWatermark
                {
                    Text = "نمایش درصد پیشرفت",
                    RunDirection = PdfRunDirection.RightToLeft,
                    Font = getWatermarkFont()
                });

        private IPdfFont getWatermarkFont()
        {
            var watermarkFont = new GenericFontProvider(
                                        AppPath.ApplicationPath + "\\fonts\\irsans.ttf",
                                        Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts\\verdana.ttf");
            watermarkFont.Color = BaseColor.LIGHT_GRAY;
            watermarkFont.Size = 50;
            return watermarkFont;
        }

table.MultipleColumnsPerPage(new MultipleColumnsPerPage
                {
                    ColumnsGap = 20,
                    ColumnsPerPage = 2,
                    ColumnsWidth = 250,
                    IsRightToLeft = true,
                    TopMargin = 7
                });

                    column.ColumnItemsTemplate(template =>
                    {
                        template.ProgressBar(progressBarColor: Color.SkyBlue, showPercentText: true);
                        template.DisplayFormatFormula(obj =>
                        {
                            if (obj == null) return "% 0";
                            return "% " + obj.ToString();
                        });
                    });

                    column.ColumnItemsTemplate(template =>
                    {
                        template.Checkmark(checkmarkFillColor: Color.Green, crossSignFillColor: Color.DarkRed);
                    });

public class Person
{
        public int Id { get; set; }                
        public string Name { get; set; }
        public int? Age { get; set; }
}

string name = null;
var list1 = ctx.Users.Where(x => x.Name == name).ToList();

SELECT
[Extent1].[Id] AS [Id],
[Extent1].[Name] AS [Name],
[Extent1].[Age] AS [Age]
FROM [dbo].[People] AS [Extent1]
WHERE [Extent1].[Name] = @p__linq__0
-- p__linq__0 (dbtype=String, size=-1, direction=Input) = null

 var list2 = ctx.Users.Where(x => !x.Age.HasValue).ToList();

int? age = null;
var list2 = ctx.Users.Where(x => object.Equals(x.Age, age)).ToList();

 var list1 = ctx.Users.Where(x => string.IsNullOrEmpty(x.Name)).ToList();

string name = null;
var list1 = ctx.Users.Where(x => name == null ? x.Name == null : x.Name == name).ToList();

 var list1 = ctx.Users.Where(x => x.Name == null).ToList();

using System;

namespace CS9Features
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}

using System;

Console.WriteLine("Hello World!");

using System;
using System.Threading.Tasks;

await MyMethodAsync();
Console.WriteLine("Hello World!");

static async Task MyMethodAsync()
{
   await Task.Yield();
}

using System;

Console.WriteLine(args[0]);

using System;
Console.WriteLine($"Hello world!");
return 1;

using System;

var greeter = new Greeter();

var helloTeacher = greeter.Greet("teacher");
var helloStudents = SayHello("students");

Console.WriteLine(helloTeacher);
Console.WriteLine(helloStudents);

static string SayHello(string name)
{
    return "Hello, " + name;
}

public class Greeter
{
    public string Greet(string name)
    {
        return "Hello, " + name;
    }
}

Top-level statements must precede namespace and type declarations. [CS9Features]csharp(CS8803)

using System;
using System.Runtime.CompilerServices;

[CompilerGenerated]
internal static class <Program>$
{
  private static void <Main>$(string[] args)
  {
   Greeter greeter = new Greeter();
   string helloTeacher = greeter.Greet("teacher");
   string helloStudents = SayHello("students");
   Console.WriteLine(helloTeacher);
   Console.WriteLine(helloStudents);

   static string SayHello(string name)
   {
    return "Hello, " + name;
   }
  }
}

using System;

Foo();

var x = 3;

int result = AddToX(4);
Console.WriteLine(result);

static void Foo()
{
    Console.WriteLine("Foo");
}

int AddToX(int y)
{
    return x + y;
}

• BackgroundColor: در صورتی که شی مورد نظر به صورت توپررسم شود، این خاصیت رنگ پس زمینه شی را مشخص می‌کند.
• BackgroundBrush: خاصیتی است که با توجه به خاصیت BackgroundColor یک الگوی پر کردن  زمینه شی می‌سازد.
• StartPoint: نقطه شروع شی را در خود نگهداری می‌کند.
• EndPoint: نقطه انتهای شی را در خود نگهداری می‌کند. (قبلا گفته شد که هر شی را در صورتی که در یک مستطیل فرض کنیم یک نقطه شروع و یک نقطه پایان دارد)
• ForeColor: رنگ قلم ترسیم شی مورد نظر را تعیین می‌کند.
• Height: ارتفاع شی مورد نظر را تعیین می‌کند ( این خصوصیت اختلاف عمودی StartPoint.Y و EndPoint.Y را محاسبه می‌کند و در زمان مقدار دهی EndPoint جدیدی ایجاد می‌کند).
• Width: عرض شی مورد نظر را تعیین می‌کند ( این خصوصیت اختلاف افقیStartPoint.X و EndPoint.X را محاسبه می‌کند و در زمان مقدار دهی EndPoint جدیدی ایجاد می‌کند).
• IsFill: این خصوصیت تعیین کننده توپر و یا توخالی بودن شی است.
• IsSelected: این خاصیت تعیین می‌کند که آیا شی انتخاب شده است یا خیر (در زمان انتخاب شی چهار مربع کوچک روی شی رسم می‌شود).
• Pen: قلم خط ترسیم شی را مشخص می‌کند. (قلم با ضخامت دلخواه)
• ShapeType: این خصوصیت نوع شی را مشخص می‌کند (این خاصیت بیشتر برای زمان پیش نمایش ترسیم شی در زمان اجراست البته به نظر خودم اضافه هست اما راه بهتری به ذهنم نرسید)
• Size: با استفاده از خصوصیات Height و Width ایجاد شده و تعیین کننده Size شی است.
• Thickness: ضخامت خط ترسیمی شی را مشخص می‌کند، این خاصیت در خصوصیت Pen استفاده شده است.
• X: مقدار افقی نقطه شروع شی را تعیین می‌کند در واقع StartPoint.X را برمی‌گرداند (این خاصیت اضافی بوده و جهت راحتی کار استفاده شده می‌توان آن را ننوشت).
• Y: مقدار عمودی نقطه شروع شی را تعیین می‌کند در واقع StartPoint.Y را برمی‌گرداند (این خاصیت اضافی بوده و جهت راحتی کار استفاده شده می‌توان آن را ننوشت).
• Zindex: در زمان ترسیم اشیا ممکن است اشیا روی هم ترسیم شوند، در واقع Zindex تعیین کننده عمق شی روی بوم گرافیکی است.
  

    public class Article
    {
        public int Id { get; set; }
        public string Title { get; set; }
        public string Body { get; set; }
        public string RegisterDate { get; set; }
        public string FileName { get; set; }
    }

public interface IEfExceptionsLogger
{
    void LogException<TResult>(DbCommand command,
        DbCommandInterceptionContext<TResult> interceptionContext);
}

using System.Data.Common;
using System.Data.Entity.Infrastructure.Interception;
 
namespace ElmahEFLogger
{
    public class EfExceptionsInterceptor : IDbCommandInterceptor
    {
        private readonly IEfExceptionsLogger _efExceptionsLogger;
 
        public EfExceptionsInterceptor(IEfExceptionsLogger efExceptionsLogger)
        {
            _efExceptionsLogger = efExceptionsLogger;
        }
 
        public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            _efExceptionsLogger.LogException(command, interceptionContext);
        }
 
        public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            _efExceptionsLogger.LogException(command, interceptionContext);
        }
 
        public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
        {
            _efExceptionsLogger.LogException(command, interceptionContext);
        }
 
        public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
        {
            _efExceptionsLogger.LogException(command, interceptionContext);
        }
 
        public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
        {
            _efExceptionsLogger.LogException(command, interceptionContext);
        }
 
        public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
        {
            _efExceptionsLogger.LogException(command, interceptionContext);
        }
    }
}

using System;
using System.Data.Common;
using System.Data.Entity.Infrastructure.Interception;
using Elmah;
 
namespace ElmahEFLogger.CustomElmahLogger
{
    public class ElmahEfExceptionsLogger : IEfExceptionsLogger
    {
        /// <summary>
        /// Manually log errors using ELMAH
        /// </summary>
        public void LogException<TResult>(DbCommand command,
            DbCommandInterceptionContext<TResult> interceptionContext)
        {
            var ex = interceptionContext.OriginalException;
            if (ex == null)
                return;
 
            var sqlData = CommandDumper.LogSqlAndParameters(command, interceptionContext);
            var contextualMessage = string.Format("{0}{1}OriginalException:{1}{2} {1}", sqlData, Environment.NewLine, ex);
 
 
            if (!string.IsNullOrWhiteSpace(contextualMessage))
            {
                ex = new Exception(contextualMessage, new ElmahEfInterceptorException(ex.Message));
            }
 
            try
            {
                ErrorSignal.FromCurrentContext().Raise(ex);
            }
            catch
            {
                ErrorLog.GetDefault(null).Log(new Error(ex));
            }
        }
    }
}

   public class ElmahEfInterceptor : EfExceptionsInterceptor
    {
        public ElmahEfInterceptor()
            : base(new ElmahEfExceptionsLogger())
        { }
    }

 DbInterception.Add(new ElmahEfInterceptor());

public class Customer
{
   public virtual string Id { get; set; }
   public virtual string Name { get; set; }
   public virtual DateTime HireDate { get; set; }
}

public class MyContext : DbContext
{
    public DbSet<Customer> Customers{ set; get; }
}

CREATE TABLE Customers (
    [Id] [int] NOT NULL IDENTITY,
    [Name] [nvarchar](max),
    [HireDate] datetime,
    CONSTRAINT [PK_Product] PRIMARY KEY ([Id])
)

Invalid object name 'dbo.Customers'.

[Table("Customers", Schema = "dbSchemaUser")]
public class Customer
{
    ...

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
   modelBuilder.Entity<Customer>().ToTable(tableName: "Customers", schemaName: "dbSchemaUser");
   ...

CREATE TABLE dbSchemaUser.Customers (
    [Id] [int] NOT NULL IDENTITY,
    [Name] [nvarchar](max),
    [HireDate] datetime,
    CONSTRAINT [PK_Product] PRIMARY KEY ([Id])
)

        public string TestNoneAsync()
        {
            var webClient = new WebClient();
            return webClient.DownloadString("http://www.google.com");
        }

        public void TestAsync()
        {
            var webClient = new WebClient();
            webClient.DownloadStringAsync(new Uri("http://www.google.com"));
            webClient.DownloadStringCompleted += webClientDownloadStringCompleted;
        }

        void webClientDownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            // use e.Result
        }

using System;
using System.Linq;
using System.Net;
using System.Windows.Forms;

namespace Async02
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnGetInfo_Click(object sender, EventArgs e)
        {
            var req = (HttpWebRequest)WebRequest.Create("http://www.google.com");
            req.Method = "HEAD";
            req.BeginGetResponse(
                asyncResult =>
                {
                    var resp = (HttpWebResponse)req.EndGetResponse(asyncResult);
                    var headersText = formatHeaders(resp.Headers);
                    txtResults.Text = headersText;
                }, null);
        }

        private string formatHeaders(WebHeaderCollection headers)
        {
            var headerString = headers.Keys.Cast<string>()
                                      .Select(header => string.Format("{0}:{1}", header, headers[header]));
            return string.Join(Environment.NewLine, headerString.ToArray());
        }
    }
}

 An exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll but was not handled in user code
Additional information: Cross-thread operation not valid: Control 'txtResults' accessed from a thread other than the thread it was created on.

        private void btnGetInfo_Click(object sender, EventArgs e)
        {
            var sync = SynchronizationContext.Current;
            var req = (HttpWebRequest)WebRequest.Create("http://www.google.com");
            req.Method = "HEAD";
            req.BeginGetResponse(
                asyncResult =>
                {
                    var resp = (HttpWebResponse)req.EndGetResponse(asyncResult);
                    var headersText = formatHeaders(resp.Headers);
                    sync.Post(delegate { txtResults.Text = headersText; }, null);
                }, null);
        }

using System;
using System.Threading.Tasks;

namespace Async01
{
    public class AsyncExample
    {
        public async Task DoWorkAsync(int parameter)
        {
            await Task.Delay(parameter);
            Console.WriteLine(parameter);
        }
    }
}

        public async Task<double> GetNumberAsync()
        {
            var generator = new Random();
            await Task.Delay(generator.Next(1000));

            return generator.NextDouble();
        }

        public async Task<double> GetSumAsync()
        {
            var leftOperand = await GetNumberAsync();
            var rightOperand = await GetNumberAsync();

            return leftOperand + rightOperand;
        }

        public async Task<double> GetProductOfSumAsync()
        {
            var leftOperand = GetSumAsync();
            var rightOperand = GetSumAsync();

            return await leftOperand * await rightOperand;
        }

 Operator '*' cannot be applied to operands of type 'System.Threading.Tasks.Task<double>' and 'System.Threading.Tasks.Task<double>'

        public async Task<string> DownloadAsync()
        {
            var webClient = new WebClient();
            return await webClient.DownloadStringTaskAsync("http://www.google.com");
        }

        public void TestDownloadAsync()
        {
            Debug.WriteLine("Before DownloadAsync");
            DownloadAsync();
            Debug.WriteLine("After DownloadAsync");
        }

 Before DownloadAsync
After DownloadAsync

 PM> Install-Package Microsoft.Bcl.Async

data-val-remote="کلمه عبور وارد شده را راحت می‌توان حدس زد!" 
data-val-remote-additionalfields="*.Password1" 
data-val-remote-type="POST" 
data-val-remote-url="/register/checkpassword"

 export class EmailValidatorDirective implements Validator {

 export class RemoteValidatorDirective implements AsyncValidator {

validate(c: AbstractControl): Promise<ValidationErrors | null> | Observable<ValidationErrors | null>;

 >ng g d CustomValidators/RemoteValidator -m custom-validators.module

import { Directive, Input } from "@angular/core";
import {
  AsyncValidator,
  AbstractControl,
  NG_ASYNC_VALIDATORS
} from "@angular/forms";
import { Http, RequestOptions, Response, Headers } from "@angular/http";
import "rxjs/add/operator/map";
import "rxjs/add/operator/distinctUntilChanged";
import "rxjs/add/operator/takeUntil";
import "rxjs/add/operator/take";
import { Observable } from "rxjs/Observable";
import { Subject } from "rxjs/Subject";

@Directive({
  selector:
    "[appRemoteValidator][formControlName],[appRemoteValidator][formControl],[appRemoteValidator][ngModel]",
  providers: [
    {
      provide: NG_ASYNC_VALIDATORS,
      useExisting: RemoteValidatorDirective,
      multi: true
    }
  ]
})
export class RemoteValidatorDirective implements AsyncValidator {
  @Input("remote-url") remoteUrl: string;
  @Input("remote-field") remoteField: string;
  @Input("remote-additional-fields") remoteAdditionalFields: string;

  constructor(private http: Http) {}

  validate(control: AbstractControl): Observable<{ [key: string]: any }> {
    if (!this.remoteUrl || this.remoteUrl === undefined) {
      return Observable.throw("`remoteUrl` is undefined.");
    }

    if (!this.remoteField || this.remoteField === undefined) {
      return Observable.throw("`remoteField` is undefined.");
    }

    const dataObject = {};
    if (
      this.remoteAdditionalFields &&
      this.remoteAdditionalFields !== undefined
    ) {
      const otherFields = this.remoteAdditionalFields.split(",");
      otherFields.forEach(field => {
        const name = field.trim();
        const otherControl = control.root.get(name);
        if (otherControl) {
          dataObject[name] = otherControl.value;
        }
      });
    }

    // This is used to signal the streams to terminate.
    const changed$ = new Subject<any>();
    changed$.next(); // This will signal the previous stream (if any) to terminate.

    const debounceTime = 400;

    return new Observable((obs: any) => {
      control.valueChanges
        .takeUntil(changed$)
        .take(1)
        .debounceTime(debounceTime)
        .distinctUntilChanged()
        .flatMap(term => {
          dataObject[this.remoteField] = term;
          return this.doRemoteValidation(dataObject);
        })
        .subscribe(
          (result: IRemoteValidationResult) => {
            if (result.result) {
              obs.next(null);
            } else {
              obs.next({
                remoteValidation: {
                  remoteValidationMessage: result.message
                }
              });
            }

            obs.complete();
          },
          error => {
            obs.next(null);
            obs.complete();
          }
        );
    });
  }

  private doRemoteValidation(data: any): Observable<IRemoteValidationResult> {
    const headers = new Headers({ "Content-Type": "application/json" }); // for ASP.NET MVC
    const options = new RequestOptions({ headers: headers });

    return this.http
      .post(this.remoteUrl, JSON.stringify(data), options)
      .map(this.extractData)
      .do(result => console.log("remoteValidation result: ", result))
      .catch(this.handleError);
  }

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

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

export interface IRemoteValidationResult {
  result: boolean;
  message: string;
}

@Directive({
  selector:
    "[appRemoteValidator][formControlName],[appRemoteValidator][formControl],[appRemoteValidator][ngModel]",
  providers: [
    {
      provide: NG_ASYNC_VALIDATORS,
      useExisting: RemoteValidatorDirective,
      multi: true
    }
  ]
})

export class RemoteValidatorDirective implements AsyncValidator {
  @Input("remote-url") remoteUrl: string;
  @Input("remote-field") remoteField: string;
  @Input("remote-additional-fields") remoteAdditionalFields: string;

<input #username="ngModel" required maxlength="8" minlength="4" type="text"
        appRemoteValidator [remote-url]="remoteUsernameValidationUrl" remote-field="FirstName"
        remote-additional-fields="email,password" class="form-control" name="username"
        [(ngModel)]="model.username">

export class UserRegisterComponent implements OnInit {
   remoteUsernameValidationUrl = "api/Employee/CheckUser";

 [remote-field]="'FirstName'"

export interface IRemoteValidationResult {
   result: boolean;
   message: string;
}

namespace AngularTemplateDrivenFormsLab.Controllers
{
    [Route("api/[controller]")]
    public class EmployeeController : Controller
    {
        [HttpPost("[action]")]
        [ResponseCache(Location = ResponseCacheLocation.None, NoStore = true)]
        public IActionResult CheckUser([FromBody] Employee model)
        {
            var remoteValidationResult = new { result = true, message = $"{model.FirstName} is fine!" };
            if (model.FirstName?.Equals("Vahid", StringComparison.OrdinalIgnoreCase) ?? false)
            {
                remoteValidationResult = new { result = false, message = "username:`Vahid` is already taken." };
            }

            return Json(remoteValidationResult);
        }
    }
}

    <div class="form-group" [class.has-error]="username.invalid && username.touched">
      <label class="control-label">User Name</label>
      <input #username="ngModel" required maxlength="8" minlength="4" type="text"
        appRemoteValidator [remote-url]="remoteUsernameValidationUrl" remote-field="FirstName"
        remote-additional-fields="email,password" class="form-control" name="username"
        [(ngModel)]="model.username">
      <div *ngIf="username.pending" class="alert alert-warning">
        Checking server, Please wait ...
      </div>
      <div *ngIf="username.invalid && username.touched">
        <div class="alert alert-danger"  *ngIf="username.errors.remoteValidation">
          {{username.errors.remoteValidation.remoteValidationMessage}}
        </div>
      </div>
    </div>

obs.next({
                remoteValidation: {
                  remoteValidationMessage: result.message
                }
              });

    // This is used to signal the streams to terminate.
    const changed$ = new Subject<any>();
    changed$.next(); // This will signal the previous stream (if any) to terminate.

    const debounceTime = 400;

    return new Observable((obs: any) => {
      control.valueChanges
        .takeUntil(changed$)
        .take(1)
        .debounceTime(debounceTime)
        .distinctUntilChanged()

 var defaults = {
            moreInfoDiv: '#MoreInfoDiv',
            progressDiv: '#Progress',
            loadInfoUrl: '/',
            loginUrl: '/login',
            errorHandler: null,
            completeHandler: null,
            noMoreInfoHandler: null
        };

if (xhr.status == 403) {
                            window.location = options.loginUrl;
                        }

    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)]
    public sealed class Mcv5AuthorizeAttribute : AuthorizeAttribute
    {
        #region Ctor

        public Mcv5AuthorizeAttribute(params string[] permissions)
            : base()
        {
            Roles = string.Join(",", permissions);
        }

        #endregion

        #region HandleUnauthorizedRequest
        protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
        {
            if (filterContext.HttpContext.Request.IsAuthenticated)
            {
                filterContext.Result = new HttpStatusCodeResult(403);

                // throw new UnauthorizedAccessException(); //to avoid multiple redirects
            }
            else
            {
                HandleAjaxRequest(filterContext);
                base.HandleUnauthorizedRequest(filterContext);
            }
        }
        #endregion

        #region Private
        private static void HandleAjaxRequest(ControllerContext filterContext)
        {
            var ctx = filterContext.HttpContext;
            if (!ctx.Request.IsAjaxRequest())
                return;

            ctx.Response.StatusCode = (int)HttpStatusCode.Forbidden; //برای درخواست‌های اجکسی اعتبار سنجی نشده
            ctx.Response.End();
        }
        #endregion
    }