Nullable Reference Types: Migrating a Codebase – A Look at New Language Features in C# 8 

Async Streams – A Look at New Language Features in C# 8 

public static void PrintNumbers()
{
    var numbers = new[] { 1,2,3,5,7,90 }; // from a data source
    foreach(var item in numbers)
    {
        Console.WriteLine(item);
    }    
}

public static void PrintNumbers(Func<int,string> formula)
{
    var numbers = new[] { 1,2,3,5,7,90 };  // from a data source
    foreach(var item in numbers)
    {
        var data = formula(item);
        Console.WriteLine(data);
    }    
}

 PrintNumbers(number => string.Format("{0:n0}",number));

 PrintNumbers((number) =>{ return string.Format("{0:n0}",number); });

using System;
using System.Web;
using System.Web.Caching;
using System.Collections.Generic;

namespace WebToolkit
{
    public static class CacheManager
    {
        public static void CacheInsert(this HttpContextBase httpContext, string key, object data, int durationMinutes)
        {
            if (data == null) return;
            httpContext.Cache.Add(
                key,
                data,
                null,
                DateTime.Now.AddMinutes(durationMinutes),
                TimeSpan.Zero,
                CacheItemPriority.AboveNormal,
                null);
        }
    }
}

var item = httpContext.Cache[key];
if (item == null)
{
    item = ReadDataFromDataSource();
    if (item == null)
          return null;

    CacheInsert(httpContext, key, item, durationMinutes);
}

using System;
using System.Web;
using System.Web.Caching;
using System.Collections.Generic;

namespace WebToolkit
{
    public static class CacheManager
    {
        public static void CacheInsert(this HttpContextBase httpContext, string key, object data, int durationMinutes)
        {
            if (data == null) return;
            httpContext.Cache.Add(
                key,
                data,
                null,
                DateTime.Now.AddMinutes(durationMinutes),
                TimeSpan.Zero,
                CacheItemPriority.AboveNormal,
                null);
        }

        public static T CacheRead<T>(this HttpContextBase httpContext, string key, int durationMinutes, Func<T> ifNullRetrievalMethod)
        {
            var item = httpContext.Cache[key];
            if (item == null)
            {
                item = ifNullRetrievalMethod();
                if (item == null)
                    return default(T);

                CacheInsert(httpContext, key, item, durationMinutes);
            }
            return (T)item;
        }
    }
}

var user = HttpContext.CacheRead(
                            "Key1",
                            15,
                            () => _usersService.FindUser(userId));

using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNet.SignalR;

namespace SignalR05.Common
{
    public class OnlineUsersHub : Hub
    {
        public static readonly ConcurrentDictionary<string, string> OnlineUsers = new ConcurrentDictionary<string, string>();

        public void UpdateUsersOnlineCount()
        {
            // آی پی معرف یک کاربر است
            // اما کانکشن آی دی معرف یک برگه جدید در مرورگر او است
            // هر کاربر می‌تواند چندین برگه را به یک سایت گشوده یا ببندد
            var ipsCount = OnlineUsers.Select(x => x.Value).Distinct().Count();
            this.Clients.All.updateUsersOnlineCount(ipsCount);
        }

        /// <summary>
        /// اگر کاربران اعتبار سنجی شده‌اند بهتر است از
        /// this.Context.User.Identity.Name
        /// بجای آی پی استفاده شود
        /// </summary>        
        protected string GetUserIpAddress()
        {
            object environment;
            if (!Context.Request.Items.TryGetValue("owin.environment", out environment))
                return null;

            object serverRemoteIpAddress;
            if (!((IDictionary<string, object>)environment).TryGetValue("server.RemoteIpAddress", out serverRemoteIpAddress))
                return null;

            return serverRemoteIpAddress.ToString();
        }

        public override Task OnConnected()
        {
            var ip = GetUserIpAddress();
            OnlineUsers.TryAdd(this.Context.ConnectionId, ip);
            UpdateUsersOnlineCount();

            return base.OnConnected();
        }

        public override Task OnReconnected()
        {
            var ip = GetUserIpAddress();
            OnlineUsers.TryAdd(this.Context.ConnectionId, ip);
            UpdateUsersOnlineCount();

            return base.OnReconnected();
        }

        public override Task OnDisconnected()
        {
            // در این حالت ممکن است مرورگر کاملا بسته شده باشد
            // یا حتی صرفا یک برگه مرورگر از چندین برگه متصل به سایت بسته شده باشند
            string ip;
            OnlineUsers.TryRemove(this.Context.ConnectionId, out ip);
            UpdateUsersOnlineCount();

            return base.OnDisconnected();
        }
    }
}

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script src="Scripts/jquery-1.6.4.min.js" type="text/javascript"></script>
    <script src="Scripts/jquery.signalR-1.1.3.min.js" type="text/javascript"></script>
    <script type="text/javascript" src='<%= ResolveClientUrl("~/signalr/hubs") %>'></script>
</head>
<body>
    <form id="form1" runat="server">
    online users count: <span id="usersCount"></span>
    </form>
    <script type="text/javascript">
        $(function () {
            $.connection.hub.logging = true;
            var onlineUsersHub = $.connection.onlineUsersHub;
            onlineUsersHub.client.updateUsersOnlineCount = function (count) {
                $('#usersCount').text(count);
            };
            $.connection.hub.start();
        });
    </script>
</body>
</html>

<system.web>
    <globalization uiCulture="fa-IR" culture="fa-IR" />
</system.web>

protected void Application_BeginRequest()
{
   Thread.CurrentThread.CurrentCulture = new CultureInfo("fa-IR");
   Thread.CurrentThread.CurrentUICulture = new CultureInfo("fa-IR");
}

public void Configure(IApplicationBuilder app)
{
    app.UseRequestLocalization(new RequestLocalizationOptions
    {
        DefaultRequestCulture = new RequestCulture(new CultureInfo("fa-IR")),
        SupportedCultures = new[]
        {
            new CultureInfo("en-US"),
            new CultureInfo("fa-IR")
        },
        SupportedUICultures = new[]
        {
            new CultureInfo("en-US"),
            new CultureInfo("fa-IR")
        }
    });

 c='en-UK'|uic='en-US'

public IActionResult SetFaLanguage()
{
    Response.Cookies.Append(
        CookieRequestCultureProvider.DefaultCookieName,
        CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(new CultureInfo("fa-IR"))),
        new CookieOptions { Expires = DateTimeOffset.UtcNow.AddYears(1) }
    );
 
    return RedirectToAction("GetTitle");
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddLocalization(options => options.ResourcesPath = "Resources");
    services.AddMvc()
        .AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
        .AddDataAnnotationsLocalization();

using System;
using System.Globalization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Localization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Localization;
using Microsoft.Extensions.Localization;
 
namespace Core1RtmEmptyTest.Controllers
{
    public class TestLocalController : Controller
    {
        private readonly IStringLocalizer<TestLocalController> _stringLocalizer;
        private readonly IHtmlLocalizer<TestLocalController> _htmlLocalizer;
 
        public TestLocalController(
            IStringLocalizer<TestLocalController> stringLocalizer,
            IHtmlLocalizer<TestLocalController> htmlLocalizer)
        {
            _stringLocalizer = stringLocalizer;
            _htmlLocalizer = htmlLocalizer;
        }
 
        public IActionResult Index()
        {
            var name = "DNT";
            var message = _htmlLocalizer["<b>Hello</b><i> {0}</i>", name];
            ViewData["Message"] = message;
            return View();
        }
 
        [HttpGet]
        public string GetTitle()
        {
            var about = _stringLocalizer["About Title"];
            return about;
        }
 
        public IActionResult SetFaLanguage()
        {
            Response.Cookies.Append(
                CookieRequestCultureProvider.DefaultCookieName,
                CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(new CultureInfo("fa-IR"))),
                new CookieOptions { Expires = DateTimeOffset.UtcNow.AddYears(1) }
            );
 
            return RedirectToAction("GetTitle");
        }
    }
}

@using Microsoft.AspNetCore.Mvc.Localization
@inject IViewLocalizer Localizer
 
@{
}
Message @ViewData["Message"]
<br/>
@Localizer["<b>Hello</b><i> {0}</i>", "DNT"]
<br/>
@Localizer["About Title"]

using System.ComponentModel.DataAnnotations;
 
namespace Core1RtmEmptyTest.ViewModels.Account
{
    public class RegisterViewModel
    {
        [Required(ErrorMessage = "EmailReq")]
        [EmailAddress(ErrorMessage = "EmailType")]
        [Display(Name = "Email")]
        public string Email { get; set; }
    }
}

// Dummy class to group shared resources
namespace Core1RtmEmptyTest
{
   public class SharedResource
   {
   }
}

 IStringLocalizer<SharedResource> sharedLocalizer

 @inject IHtmlLocalizer<SharedResource> SharedLocalizer

public static string FixGmailDots(string email)
{
    if (string.IsNullOrWhiteSpace(email))
        return string.Empty;
 
    email = email.ToLowerInvariant().Trim();
    var emailParts = email.Split('@');
    var name = emailParts[0].Replace(".", string.Empty).Replace("+", string.Empty);
    var emailDomain = emailParts[1];
 
    string[] domainsAllowedDots =
    {
        "gmail.com",
        "facebook.com"
    };
 
    var isFromDomainsAllowedDots = domainsAllowedDots.Any(domain => emailDomain.Equals(domain));
    return !isFromDomainsAllowedDots ? email : string.Format("{0}@{1}", name, emailDomain);
}

 friendlyName = friendlyName.ApplyCorrectYeKe().RemoveDiacritics().CleanUnderLines().RemovePunctuation();
var trimmedFriendlyName = friendlyName.Trim().Replace(" ", "");

public static string CleanUnderLines(string text)
{
    if (string.IsNullOrWhiteSpace(text))
        return string.Empty;
 
    const char chr1600 = (char)1600; //ـ=1600
    const char chr8204 = (char)8204; //‌=8204
 
    return text.Replace(chr1600.ToString(CultureInfo.InvariantCulture), "")
               .Replace(chr8204.ToString(CultureInfo.InvariantCulture), "");
}

 public static string RemovePunctuation(string text)
{
 return string.IsNullOrWhiteSpace(text) ? string.Empty : new string(text.Where(c => !char.IsPunctuation(c)).ToArray());
}

using System.Data.Entity.ModelConfiguration;
 
namespace MvcPluginMasterApp.Plugin1.DomainClasses
{
    public class News
    {
        public int Id { set; get; }
 
        public string Title { set; get; }
 
        public string Body { set; get; }
    }
 
    public class NewsConfig : EntityTypeConfiguration<News>
    {
        public NewsConfig()
        {
            this.ToTable("Plugin1_News");
            this.HasKey(news => news.Id);
            this.Property(news => news.Title).IsRequired().HasMaxLength(500);
            this.Property(news => news.Body).IsOptional().IsMaxLength();
        }
    }
}

 PM> install-package EntityFramework

public class MvcPluginMasterAppContext : DbContext, IUnitOfWork
{
    public DbSet<Category> Categories { set; get; }
    public DbSet<Product> Products { set; get; }

namespace MvcPluginMasterApp.PluginsBase
{
    public interface IUnitOfWork : IDisposable
    {
        IDbSet<TEntity> Set<TEntity>() where TEntity : class;
        int SaveAllChanges();
        void MarkAsChanged<TEntity>(TEntity entity) where TEntity : class;
        IList<T> GetRows<T>(string sql, params object[] parameters) where T : class;
        IEnumerable<TEntity> AddThisRange<TEntity>(IEnumerable<TEntity> entities) where TEntity : class;
        void SetDynamicEntities(Type[] dynamicTypes);
        void ForceDatabaseInitialize();
        void SetConfigurationsAssemblies(Assembly[] assembly);
    }
}

namespace MvcPluginMasterApp.DataLayer.Context
{
    public class MvcPluginMasterAppContext : DbContext, IUnitOfWork
    {
        private readonly IList<Assembly> _configurationsAssemblies = new List<Assembly>();
        private readonly IList<Type[]> _dynamicTypes = new List<Type[]>(); 
 
        public void ForceDatabaseInitialize()
        {
            Database.Initialize(force: true);
        }
 
        public void SetConfigurationsAssemblies(Assembly[] assemblies)
        {
            if (assemblies == null) return;
 
            foreach (var assembly in assemblies)
            {
                _configurationsAssemblies.Add(assembly);
            }
        }
 
        public void SetDynamicEntities(Type[] dynamicTypes)
        {
            if (dynamicTypes == null) return;
            _dynamicTypes.Add(dynamicTypes);
        }
 
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            addConfigurationsFromAssemblies(modelBuilder);
            addPluginsEntitiesDynamically(modelBuilder);
            base.OnModelCreating(modelBuilder);
        }
 
        private void addConfigurationsFromAssemblies(DbModelBuilder modelBuilder)
        {
            foreach (var assembly in _configurationsAssemblies)
            {
                modelBuilder.Configurations.AddFromAssembly(assembly);
            }
        }
 
        private void addPluginsEntitiesDynamically(DbModelBuilder modelBuilder)
        {
            foreach (var types in _dynamicTypes)
            {
                foreach (var type in types)
                {
                    modelBuilder.RegisterEntityType(type);
                }
            }
        }
    }
}

namespace MvcPluginMasterApp.PluginsBase
{
    public interface IPlugin
    {
        EfBootstrapper GetEfBootstrapper();
        //...به همراه سایر متدهای مورد نیاز
    }
 
    public class EfBootstrapper
    {
        /// <summary>
        /// Assemblies containing EntityTypeConfiguration classes.
        /// </summary>
        public Assembly[] ConfigurationsAssemblies { get; set; }
 
        /// <summary>
        /// Domain classes.
        /// </summary>
        public Type[] DomainEntities { get; set; }
 
        /// <summary>
        /// Custom Seed method.
        /// </summary>
        public Action<IUnitOfWork> DatabaseSeeder { get; set; }
    } 
}

namespace MvcPluginMasterApp.Plugin1
{
    public class Plugin1 : IPlugin
    {
        public EfBootstrapper GetEfBootstrapper()
        {
            return new EfBootstrapper
            {
                DomainEntities = new[] { typeof(News) },
                ConfigurationsAssemblies = new[] { typeof(NewsConfig).Assembly },
                DatabaseSeeder = uow =>
                {
                    var news = uow.Set<News>();
                    if (news.Any())
                    {
                        return;
                    }
 
                    news.Add(new News
                    {
                        Title = "News 1",
                        Body = "news 1 news 1 news 1 ...."
                    });
 
                    news.Add(new News
                    {
                        Title = "News 2",
                        Body = "news 2 news 2 news 2 ...."
                    });
                }
            };
        }

[assembly: PreApplicationStartMethod(typeof(EFBootstrapperStart), "Start")]
namespace MvcPluginMasterApp
{
    public static class EFBootstrapperStart
    {
        public static void Start()
        {
            var plugins = SmObjectFactory.Container.GetAllInstances<IPlugin>().ToList();
            using (var uow = SmObjectFactory.Container.GetInstance<IUnitOfWork>())
            {
                initDatabase(uow, plugins);
                runDatabaseSeeders(uow, plugins);
            }
        }
 
        private static void initDatabase(IUnitOfWork uow, IEnumerable<IPlugin> plugins)
        {
            foreach (var plugin in plugins)
            {
                var efBootstrapper = plugin.GetEfBootstrapper();
                if (efBootstrapper == null) continue;
 
                uow.SetDynamicEntities(efBootstrapper.DomainEntities);
                uow.SetConfigurationsAssemblies(efBootstrapper.ConfigurationsAssemblies);
            }
 
            Database.SetInitializer(new MigrateDatabaseToLatestVersion<MvcPluginMasterAppContext, Configuration>());
            uow.ForceDatabaseInitialize();
        }
 
        private static void runDatabaseSeeders(IUnitOfWork uow, IEnumerable<IPlugin> plugins)
        {
            foreach (var plugin in plugins)
            {
                var efBootstrapper = plugin.GetEfBootstrapper();
                if (efBootstrapper == null || efBootstrapper.DatabaseSeeder == null) continue;
 
                efBootstrapper.DatabaseSeeder(uow);
                uow.SaveAllChanges();
            }
        }
    }
}