00000000 00000000 00000000 00001100

00000000 00000000 00000000 00000110

uint e = 0b_1001;
Console.WriteLine($"Before: {Convert.ToString(e, toBase: 2),4}");
// Before: 1001

uint f = e >> 2;
Console.WriteLine($"After:  {Convert.ToString(f, toBase: 2).PadLeft(4, '0'),4}");
// After:  0010

10000000 00000000 00000000 01100000

11111000 00000000 00000000 00000110

int x = -8;
Console.WriteLine($"Before: {x,11}, hex: {x,8:x}, binary: {Convert.ToString(x, toBase: 2),32}");
// Before: -8, hex: fffffff8, binary: 11111111111111111111111111111000

int y = x >> 2;
Console.WriteLine($"After  >>: {y,11}, hex: {y,8:x}, binary: {Convert.ToString(y, toBase: 2),32}");
// After  >>: -2, hex: fffffffe, binary: 11111111111111111111111111111110

int z = x >>> 2;
Console.WriteLine($"After >>>: {z,11}, hex: {z,8:x}, binary: {Convert.ToString(z, toBase: 2).PadLeft(32, '0'),32}");
// After >>>:  1073741822, hex: 3ffffffe, binary: 00111111111111111111111111111110

public static int UnsignedRightShift(this int signed, int places)
{
    unchecked
    {
        var unsigned = (uint)signed;
        unsigned >>= places;
        return (int)unsigned;
    }
}

public static long UnsignedRightShift(this long signed, int places)
{
    unchecked
    {
        var unsigned = (ulong)signed;
        unsigned >>= places;
        return (long)unsigned;
    }
}

ASP.NET Core 2.0 – What’s New  

Meeting the Joel Test 2.0 

var connection = new SqliteConnection("Data Source=:memory:");
connection.Open();

var createCommand = connection.CreateCommand();
createCommand.CommandText =
            @"
                CREATE TABLE persian_letter (
                    value TEXT
                );

                INSERT INTO persian_letter
                VALUES ('ا'),('ب'),('پ'),('ت'),('ث'),('ج'),('چ'),('ح'),('خ'),('د'),('ذ'),('ر'),('ز'),('ژ'),('س'),('ش'),
                       ('ص'),('ض'),('ط'),('ظ'),('ع'),('غ'),('ف'),('ق'),('ک'),('گ'),('ل'),('م'),('ن'),('و'),('ه'),('ی');
            ";
createCommand.ExecuteNonQuery();

var queryCommand = connection.CreateCommand();
queryCommand.CommandText =
            @"
                SELECT value
                FROM persian_letter
                order by value
            ";
var reader = queryCommand.ExecuteReader();
var sortedDbItems = new List<string>();
while (reader.Read())
{
    sortedDbItems.Add($"{reader["value"]}");
}

connection.CreateCollation("PersianCollationNoCase", (x, y) => string.Compare(x, y, ignoreCase: true));

SELECT value
FROM persian_letter
order by value COLLATE PersianCollationNoCase

connection.CreateCollation("PersianCollationNoCaseYekeInsensitive",
(x, y) => string.Compare(x.ApplyCorrectYeKe(), y.ApplyCorrectYeKe(), ignoreCase: true));

CREATE TABLE persian_letter (
value TEXT
);
INSERT INTO persian_letter
VALUES ('ی'),('ک');

SELECT count()
FROM persian_letter
WHERE value = 'ی' COLLATE PersianCollationNoCaseYekeInsensitive

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>

An unhandled exception occurred while processing the request
  InvalidOperationException: Unable to resolve service for type 'WebApplication1.Models.ICoreService' while attempting to activate 'WebApplication1.Controllers.HomeController'
Microsoft.Extensions.Internal.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)

private static readonly Lazy<Container> _containerBuilder =
            new Lazy<Container>(defaultContainer, LazyThreadSafetyMode.ExecutionAndPublication);

Proposed features & enhancements in C# 7.2:
Non-trailing named arguments
private protected
Readonly references
conditional-ref