var fileName = Path.GetFileName(filePath);
                if (Request.Browser.Browser == "IE")
                {
                    string attachment = string.Format("attachment; filename=\"{0}\"", Server.UrlPathEncode(fileName));
                    Response.AddHeader("Content-Disposition", attachment);
                }
                return File(filePath, "application/octet-stream", fileName);

interface IProduct
{
       //  در اینجا  برحسب نیاز فیلدها  و یا امضای متد‌ها قرار می‌گیرند 
}

class ConcreteProductA : IProduct
{
      // A پیاده سازی 
}
 
class ConcreteProductB : IProduct
{
      // B پیاده سازی 
}

abstract class Creator
{
          // این متد بر اساس نوع ورودی انتخاب مناسب را انجام و باز می‌گرداند
           public abstract IProduct FactoryMethod(string type);
}

class ConcreteCreator : Creator
{
     public override IProduct FactoryMethod(string type)
    {
            switch (type)
           {
                case "A": return new ConcreteProductA();
                case "B": return new ConcreteProductB();
                default: throw new ArgumentException("Invalid type", "type");
           }
     }
}

var data = 
new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
// پرس و جوی عادی
var q1 = from i in data select i;
// پرس و جو به شیوه موازی
var q2 = from i in data.AsParallel() select i;

//نتیجه اجرای q1
0 1 2 3 4 5 6 7 8 9 10
//نتیجه اجرای q2
0 6 1 7 2 8 3 9 4 10 5

var q3 = from i in data.AsParallel() orderby i  select i;

var q4 = from i in data.AsParallel().AsOrdered() select i;

> create-react-app sample-04
> cd sample-04
> npm start

> npm install --save bootstrap

import "bootstrap/dist/css/bootstrap.css";

import React, { Component } from 'react';

import React, { Component } from "react";

class Counter extends Component {
  render() {
    return <h1>Hello world!</h1>;
  }
}

export default Counter;

import Counter from "./components/counter";

 ReactDOM.render(<Counter />, document.getElementById("root"));

  render() {
    return <h1>Hello world!</h1><button>Increment</button>;
  }

  render() {
    return (
      <div>
        <h1>Hello world!</h1>
        <button>Increment</button>
      </div>
    );

return ;
  <div></div>

return (
  <div></div>
);

    return (
      <React.Fragment>
        <h1>Hello world!</h1>
        <button>Increment</button>
      </React.Fragment>
    );

import React, { Component } from "react";

class Counter extends Component {
  state = {
    count: 0
  };

  render() {
    return (
      <React.Fragment>
        <span>{this.state.count}</span>
        <button>Increment</button>
      </React.Fragment>
    );
  }
}

export default Counter;

import React, { Component } from "react";

class Counter extends Component {
  state = {
    count: 0
  };

  render() {
    return (
      <React.Fragment>
        <span>{this.formatCount()}</span>
        <button>Increment</button>
      </React.Fragment>
    );
  }

  formatCount() {
    const { count } = this.state; // Object Destructuring
    return count === 0 ? "Zero" : count;
  }
}

export default Counter;

  formatCount() {
    const { count } = this.state; // Object Destructuring
    return count === 0 ? <h1>Zero</h1> : count;
  }

  state = {
    count: 0,
    imageUrl: "/logo192.png"
  };

  render() {
    return (
      <React.Fragment>
        <img src={this.state.imageUrl} alt="" />
        <span>{this.formatCount()}</span>
        <button>Increment</button>
      </React.Fragment>
    );
  }

    return (
      <React.Fragment>
        <img src={this.state.imageUrl} alt="" />
        <span className="badge badge-primary m-2">{this.formatCount()}</span>
        <button className="btn btn-secondary btn-sm">Increment</button>
      </React.Fragment>
    );

  styles = {
    fontSize: 50,
    fontWeight: "bold"
  };

    return (
      <React.Fragment>
        <img src={this.state.imageUrl} alt="" />
        <span style={this.styles} className="badge badge-primary m-2">
          {this.formatCount()}
        </span>
        <button className="btn btn-secondary btn-sm">Increment</button>
      </React.Fragment>
    );

<button style={{ fontSize: 30 }} className="btn btn-secondary btn-sm">

  render() {
    let classes = "badge m-2 badge-";
    classes += this.state.count === 0 ? "warning" : "primary";

    return (
      <React.Fragment>
        <img src={this.state.imageUrl} alt="" />
        <span style={this.styles} className={classes}>
          {this.formatCount()}
        </span>
        <button style={{ fontSize: 30 }} className="btn btn-secondary btn-sm">
          Increment
        </button>
      </React.Fragment>
    );

  render() {
    let classes = this.getBadgeClasses();
    // ...
  }

  getBadgeClasses() {
    let classes = "badge m-2 badge-";
    classes += this.state.count === 0 ? "warning" : "primary";
    return classes;
  }

<span style={this.styles} className={this.getBadgeClasses()}>

• Which API are you using? – Google+ API
• Where will you be calling the API from? – Web server (e.g. node.js, Tomcat)
• What data will you be accessing? – User data

https://localhost:6001/signin-google

{
  "Authentication": {
    "Google": {
      "ClientId": "xxxx",
      "ClientSecret": "xxxx"
    }
  }
}

namespace DNT.IDP
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
   // ... 

            services.AddAuthentication()
                .AddGoogle(authenticationScheme: "Google", configureOptions: options =>
                {
                    options.SignInScheme = IdentityServerConstants.ExternalCookieAuthenticationScheme;
                    options.ClientId = Configuration["Authentication:Google:ClientId"];
                    options.ClientSecret = Configuration["Authentication:Google:ClientSecret"];
                });
        }

 public const string ExternalCookieAuthenticationScheme = "idsrv.external";

namespace DNT.IDP.Controllers.Account
{
    [SecurityHeaders]
    [AllowAnonymous]
    public class ExternalController : Controller
    {
        public async Task<IActionResult> Callback()
        {
            var result = await HttpContext.AuthenticateAsync(IdentityServer4.IdentityServerConstants.ExternalCookieAuthenticationScheme);
            var returnUrl = result.Properties.Items["returnUrl"] ?? "~/";

            var (user, provider, providerUserId, claims) = await FindUserFromExternalProvider(result);
            if (user == null)
            {
                // user = AutoProvisionUser(provider, providerUserId, claims);
                
                var returnUrlAfterRegistration = Url.Action("Callback", new { returnUrl = returnUrl });
                var continueWithUrl = Url.Action("RegisterUser", "UserRegistration" ,
                    new { returnUrl = returnUrlAfterRegistration, provider = provider, providerUserId = providerUserId });
                return Redirect(continueWithUrl);
            }

var (user, provider, providerUserId, claims) = await FindUserFromExternalProvider(result);  
foreach (var claim in claims)
{
   _logger.LogInformation($"External provider[{provider}] info-> claim:{claim.Type}, value:{claim.Value}");
}

External provider[Google] info-> claim:http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name, value:Vahid N.
External provider[Google] info-> claim:http://schemas.xmlsoap.org/ws/2005/05/identity/claims/givenname, value:Vahid
External provider[Google] info-> claim:http://schemas.xmlsoap.org/ws/2005/05/identity/claims/surname, value:N.
External provider[Google] info-> claim:urn:google:profile, value:https://plus.google.com/105013528531611201860
External provider[Google] info-> claim:http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress, value:my.name@gmail.com

        [HttpGet]
        public async Task<IActionResult> Callback()
        {
            // ...

            var (user, provider, providerUserId, claims) = await FindUserFromExternalProvider(result);
            if (user == null)
            {
                // user wasn't found by provider, but maybe one exists with the same email address?  
                if (provider == "Google")
                {
                    // email claim from Google
                    var email = claims.FirstOrDefault(c =>
                        c.Type == "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress");
                    if (email != null)
                    {
                        var userByEmail = await _usersService.GetUserByEmailAsync(email.Value);
                        if (userByEmail != null)
                        {
                            // add Google as a provider for this user
                            await _usersService.AddUserLoginAsync(userByEmail.SubjectId, provider, providerUserId);

                            // redirect to ExternalLoginCallback
                            var continueWithUrlAfterAddingUserLogin =
                                Url.Action("Callback", new {returnUrl = returnUrl});
                            return Redirect(continueWithUrlAfterAddingUserLogin);
                        }
                    }
                }


                var returnUrlAfterRegistration = Url.Action("Callback", new {returnUrl = returnUrl});
                var continueWithUrl = Url.Action("RegisterUser", "UserRegistration",
                    new {returnUrl = returnUrlAfterRegistration, provider = provider, providerUserId = providerUserId});
                return Redirect(continueWithUrl);
            }

using System;
using System.Threading.Tasks;

namespace Listing_01 {

class Listing_01 {

static void Main(string[] args) {
  Task.Factory.StartNew(() => {
         Console.WriteLine("Hello World");
  });

  // wait for input before exiting
  Console.WriteLine("Main method complete. Press enter to finish.");
  Console.ReadLine();
 }
}

using System.Threading.Tasks;

using System.Threading;

Task.Factory.StartNew(() => {
   Console.WriteLine("Hello World");
});

Main method complete. Press enter to finish.

Hello World

Task task1 = new Task(new Action(printMessage));

Task task2 = new Task(delegate {
   printMessage();
});

Task task3 = new Task(() => printMessage());

Task task4 = new Task(() => {
   printMessage();
});

using System;
using System.Threading.Tasks;

namespace Listing_02 {

class Listing_02 {

static void Main(string[] args) {

   // use an Action delegate and a named method
   Task task1 = new Task(new Action(printMessage));

   // use a anonymous delegate
   Task task2 = new Task(delegate {
   printMessage();
});

  // use a lambda expression and a named method
  Task task3 = new Task(() => printMessage());

  // use a lambda expression and an anonymous method
  Task task4 = new Task(() => {
    printMessage();
  });
  task1.Start();
  task2.Start();
  task3.Start();
  task4.Start();

  // wait for input before exiting
  Console.WriteLine("Main method complete. Press enter to finish.");
  Console.ReadLine();
 }

 static void printMessage() {
  Console.WriteLine("Hello World");
  }
 }
}

Main method complete. Press enter to finish.

Hello World

Hello World

Hello World

Hello World

using MyConsole = System.Console;

MyConsole.WriteLine("Test console");

// Namespace alias
using SuperJSON = System.Text.Json;
var document = SuperJSON.JsonSerializer.Serialize("{}");

// Type alias
using SuperJSON = System.Text.Json.JsonSerializer;
var document = SuperJSON.Serialize("{}");

using UnityEngine;
using System;

Random rnd = new Random();

var rnd = new System.Random();

using Random = System.Random;

using Ints = int[];
using DatabaseInt = int?;
using OptionalFloat = float?;
using Grade= decimal;
using Point3D = (int, int, int);
using Person = (string name, int age, string country);
using unsafe P = char*;
using Matrix = int[][];

Matrix aMatrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];

using MyConsole = System.Console;
using Person = (string name, int age, string country);

Person person = new("User 1", 33, "Iran");
Console.WriteLine(person);
PrintPerson(person);

MyConsole.WriteLine("Test console");

static void PrintPerson(Person person)
{
   MyConsole.WriteLine($"{person.name}, {person.age}, {person.country}");
}

(User 1, 33, Iran)
User 1, 33, Iran
Test console

using Companies = System.Collections.Generic.List<Company>;

Companies GetCompanies()
{
   // logic here
}

class Company
{
   public string Name;
   public int Id;
}

using EventHandlers = System.Collections.Generic.IEnumerable<System.Func<System.Threading.Tasks.Task>>;

using Country = (string Abbreviation, string Name);

Country GetCountry(string abbreviation)
{
   // Logic here
}

List<Country> GetCountries()
{
   // Logic here
}

using Ints = int[];
using DatabaseInt = int?;
using OptionalFloat = float?;

using FluentValidationSample.Models;
using Microsoft.AspNetCore.Mvc;

namespace FluentValidationSample.Web.Controllers
{
    public class HomeController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }

        [HttpPost]
        public IActionResult RegisterValidateManually(RegisterModel model)
        {
            var validator = new RegisterModelValidator();
            var validationResult = validator.Validate(model);
            if (!validationResult.IsValid)
            {
                return BadRequest(validationResult.Errors[0].ErrorMessage);
            }

            // TODO: Save the model

            return Ok();
        }
    }
}

public IActionResult RegisterValidateManually(RegisterModel model)
{
    var validator = new RegisterModelValidator();
    var validationResult = validator.Validate(model);
    if (!validationResult.IsValid)
    {
       validationResult.AddToModelState(ModelState, null);
       return BadRequest(ModelState);
    }

    // TODO: Save the model

    return Ok();
}

namespace FluentValidationSample.Web
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddTransient<IValidator<RegisterModel>, RegisterModelValidator>();
            services.AddControllersWithViews();
        }

namespace FluentValidationSample.Web.Controllers
{
    public class HomeController : Controller
    {
        private readonly IValidator<RegisterModel> _registerModelValidator;

        public HomeController(IValidator<RegisterModel> registerModelValidator)
        {
            _registerModelValidator = registerModelValidator;
        }

        [HttpPost]
        public IActionResult RegisterValidatorInjection(RegisterModel model)
        {
            var validationResult = _registerModelValidator.Validate(model);
            if (!validationResult.IsValid)
            {
                return BadRequest(validationResult.Errors[0].ErrorMessage);
            }

            // TODO: Save the model

            return Ok();
        }
    }
}

namespace FluentValidationSample.Web
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddTransient<IValidator<RegisterModel>, RegisterModelValidator>();
            services.AddControllersWithViews().AddFluentValidation();
        }

namespace FluentValidationSample.Web.Controllers
{
    public class HomeController : Controller
    {
        [HttpPost]
        public IActionResult RegisterValidatorAutomatically(RegisterModel model)
        {
            if (!ModelState.IsValid)
            {
                // re-render the view when validation failed.
                return View(model);
            }

            // TODO: Save the model

            return Ok();
        }
    }
}

namespace FluentValidationSample.Web.Controllers
{
    [Route("[controller]")]
    [ApiController]
    public class HomeController : Controller
    {
        [HttpPost]
        public IActionResult RegisterValidatorAutomatically(RegisterModel model)
        {
            // TODO: Save the model

            return Ok();
        }
    }
}

{
    "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
    "title": "One or more validation errors occurred.",
    "status": 400,
    "traceId": "|84df05e2-41e0d4841bb61293.",
    "errors": {
        "FirstName": [
            "'First Name' must not be empty."
        ]
    }
}

        public void ConfigureServices(IServiceCollection services)
        {
            // ...

            // override modelstate
            services.Configure<ApiBehaviorOptions>(options =>
            {
                options.InvalidModelStateResponseFactory = context =>
                {
                    var errors = context.ModelState.Values.SelectMany(x => x.Errors.Select(p => p.ErrorMessage)).ToList();
                    return new BadRequestObjectResult(new
                    {
                        Code = "00009",
                        Message = "Validation errors",
                        Errors = errors
                    });
                };
            });
        }

namespace FluentValidationSample.Web
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllersWithViews().AddFluentValidation(
                fv => fv.RegisterValidatorsFromAssemblyContaining<RegisterModelValidator>()
            );
        }

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllersWithViews().AddFluentValidation(
       fv =>
       {
           fv.RegisterValidatorsFromAssemblyContaining<RegisterModelValidator>();
           fv.RunDefaultMvcValidationAfterFluentValidationExecutes = false;
       }
    );
}