using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

namespace jQueryMvcSample01.Models
{
    public class User
    {
        [Required(ErrorMessage = "(*)"), DisplayName("نام")]
        public string Name { set; get; }

        public PhoneInfo PhoneInfo { set; get; }
    }

    public class PhoneInfo
    {
        [Required(ErrorMessage = "(*)"), DisplayName("تلفن")]
        public string Phone { get; set; }

        [Required(ErrorMessage = "(*)"), DisplayName("پیش شماره")]
        public string Ext { get; set; }
    }
}

using System.Web.Mvc;
using jQueryMvcSample01.Models;
using jQueryMvcSample01.Security;

namespace jQueryMvcSample01.Controllers
{
    public class HomeController : Controller
    {
        [HttpGet]
        public ActionResult Index()
        {
            return View(); //نمایش فرم
        }

        [HttpPost]
        [AjaxOnly] //فقط در حالت ای‌جکس قابل دسترسی باشد
        [ValidateAntiForgeryToken]
        public ActionResult Index(User user)
        {
            if (this.ModelState.IsValid)
            {
                // ذخیره سازی در بانک اطلاعاتی ...
                System.Threading.Thread.Sleep(3000);

                return Content("ok");//اعلام موفقیت آمیز بودن کار
            }

            return Content(null);//ارسال خطا
        }
    }
}

// <![CDATA[
(function ($) {
    $.fn.PostMvcFormAjax = function (options) {
        var defaults = {
            postUrl: '/',
            loginUrl: '/login',
            beforePostHandler: null,
            completeHandler: null,
            errorHandler: null
        };
        var options = $.extend(defaults, options);

        var validateForm = function (form) {
            //فعال سازی دستی اعتبار سنجی جی‌کوئری
            var val = form.validate();
            val.form();
            return val.valid();
        };

        return this.each(function () {
            var form = $(this);
            //اگر فرم اعتبار سنجی نشده، اطلاعات آن ارسال نشود
            if (!validateForm(form)) return;

            //در اینجا می‌توان مثلا دکمه‌ای را غیرفعال کرد
            if (options.beforePostHandler)
                options.beforePostHandler(this);

            //اطلاعات نباید کش شوند
            $.ajaxSetup({ cache: false });

            $.ajax({
                type: "POST",
                url: options.postUrl,
                data: form.serialize(), //تمام فیلدهای فرم منجمله آنتی فرجری توکن آن‌را ارسال می‌کند
                complete: function (xhr, status) {
                    var data = xhr.responseText;
                    if (xhr.status == 403) {
                        window.location = options.loginUrl; //در حالت لاگین نبودن شخص اجرا می‌شود
                    }
                    else if (status === 'error' || !data) {
                        if (options.errorHandler)
                            options.errorHandler(this);
                    }
                    else {
                        if (options.completeHandler)
                            options.completeHandler(this);
                    }
                }

            });
        });
    };
})(jQuery);
// ]]>

@model jQueryMvcSample01.Models.User
@{
    ViewBag.Title = "تعریف کاربر";
    var postUrl = Url.Action(actionName: "Index", controllerName: "Home");
}
@using (Html.BeginForm(actionName: "Index", controllerName: "Home",
                       method: FormMethod.Post,
                       htmlAttributes: new { id = "UserForm" }))
{
    @Html.ValidationSummary(true)
    @Html.AntiForgeryToken()

    <fieldset>
        <legend>تعریف کاربر</legend>
        <div class="editor-label">
            @Html.LabelFor(model => model.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Name)
            @Html.ValidationMessageFor(model => model.Name)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.PhoneInfo.Ext)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.PhoneInfo.Ext)
            @Html.ValidationMessageFor(model => model.PhoneInfo.Ext)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.PhoneInfo.Phone)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.PhoneInfo.Phone)
            @Html.ValidationMessageFor(model => model.PhoneInfo.Phone)
        </div>
        <p>
            <input type="submit" id="btnSave" value="ارسال" />
        </p>
    </fieldset>
}
@section JavaScript
{
    <script type="text/javascript">
        $(document).ready(function () {
            $("#btnSave").click(function (event) {
                //جلوگیری از پست بک به سرور
                event.preventDefault();

                var button = $(this);

                $("#UserForm").PostMvcFormAjax({
                    postUrl: '@postUrl',
                    loginUrl: '/login',
                    beforePostHandler: function () {
                        //غیرفعال سازی دکمه ارسال
                        button.attr('disabled', 'disabled');
                        button.val("...");
                    },
                    completeHandler: function () {
                        //فعال سازی مجدد دکمه ارسال
                        alert('انجام شد');
                        button.removeAttr('disabled');
                        button.val("ارسال");
                    },
                    errorHandler: function () {
                        alert('خطایی رخ داده است');
                    }
                });
            });
        });
    </script>
}

 @Html.EditorFor(model => model.PhoneInfo.Phone)

<head>
    <title>@ViewBag.Title</title>    
    <link href="@Url.Content("Content/Site.css")" rel="stylesheet" type="text/css" />
    <script src="@Url.Content("~/Scripts/jquery-1.9.1.min.js")" type="text/javascript"></script>
    <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script>
    <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
    <script src="@Url.Content("~/Scripts/jquery.PostMvcFormAjax.js")" type="text/javascript"></script>
    @RenderSection("JavaScript", required: false)
</head>

{
    "userIsAuthorizedForCourseTranscripts": false,
    "modules": [
        {
            "title": "Course Overview",
            "clips": [
                {
                    "title": "Course Overview",
                    "playerParameters": "author=scott-allen&name=aspdotnet-core-1-0-fundamentals-m0&mode=live&clip=0&course=aspdotnet-core-1-0-fundamentals",
                    "transcripts": [ ]
                }
            ]
        },
        {
            "title": "Building Your First ASP.NET Core Application",
            "clips": [
                {
                    "title": "Introduction",
                    "playerParameters": "author=scott-allen&name=aspdotnet-core-1-0-fundamentals-m1&mode=live&clip=0&course=aspdotnet-core-1-0-fundamentals",
                    "transcripts": [
                        {
                            "displayTime": 0.0,
                            "text": "Hi! This is Scott, and this course will help you build your first application with ASP.NET Core."
                        },
                        {
                            "displayTime": 7.0,
                            "text": "In this course, we'll be using Visual Studio and the new ASP.NET Framework to build a web application that"
                        }
                    ]
                }
            ]
        }
    ]
}

public class PluralsightCourse
{
    public bool UserIsAuthorizedForCourseTranscripts { get; set; }
    public PluralsightCourseItems[] Modules { get; set; }
}
public class PluralsightCourseItems
{
    public string Title { get; set; }
    public PluralsightCourseClip[] Clips { get; set; }
}
public class PluralsightCourseClip
{
    public string Title { get; set; }
    public string PlayerParameters { get; set; }
    public PluralsightCourseClipTranscript[] Transcripts { get; set; }
}
public class PluralsightCourseClipTranscript
{
    public float DisplayTime { get; set; }
    public string Text { get; set; }
}

public static PluralsightCourse ProcessJsonFile(string jsonData)
{
    return JsonConvert.DeserializeObject<PluralsightCourse>(jsonData);
}

namespace Microsoft.Extensions.Hosting
{
    public interface IHostedService
    {
        Task StartAsync(CancellationToken cancellationToken);
        Task StopAsync(CancellationToken cancellationToken);
    }
}

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace MvcTest
{
    public class SampleHostedService : IHostedService
    {
        private readonly ILogger<SampleHostedService> _logger;

        public SampleHostedService(ILogger<SampleHostedService> logger)
        {
            _logger = logger;
        }

        public async Task StartAsync(CancellationToken cancellationToken)
        {
            _logger.LogInformation("Starting Hosted service");

            while (!cancellationToken.IsCancellationRequested)
            {
                _logger.LogInformation("Hosted service executing - {0}", DateTime.Now);
                await Task.Delay(TimeSpan.FromSeconds(2), cancellationToken);
            }
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            _logger.LogInformation("Stopping Hosted service");
            return Task.CompletedTask;
        }
    }
}

namespace MvcTest
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSingleton<IHostedService, SampleHostedService>();

services.AddHostedService<SampleHostedService>();

 public void Configure(IApplicationBuilder app, IHostingEnvironment env)

Startup.cs(82,56): error CS0104: 'IHostingEnvironment' is an ambiguous reference between
'Microsoft.AspNetCore.Hosting.IHostingEnvironment' and 'Microsoft.Extensions.Hosting.IHostingEnvironment'

D:\MvcTest>dotnet run
info: MvcTest.SampleHostedService[0]
      Starting Hosted service
info: MvcTest.SampleHostedService[0]
      Hosted service executing - 02/19/2019 14:45:10
info: MvcTest.SampleHostedService[0]
      Hosted service executing - 02/19/2019 14:45:12
info: MvcTest.SampleHostedService[0]
      Hosted service executing - 02/19/2019 14:45:14
Ctrl+C
Application is shutting down...
Hosting environment: Development
Content root path: D:\MvcTest
Now listening on: https://localhost:5001
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

namespace Microsoft.Extensions.Hosting
{
    public abstract class BackgroundService : IHostedService, IDisposable
    {
        protected BackgroundService();
        public virtual void Dispose();
        public virtual Task StartAsync(CancellationToken cancellationToken);
        public virtual Task StopAsync(CancellationToken cancellationToken);
        protected abstract Task ExecuteAsync(CancellationToken stoppingToken);
    }
}

namespace MvcTest
{
    public class PrinterHostedService : BackgroundService
    {
        private readonly ILogger<SampleHostedService> _logger;

        public PrinterHostedService(ILogger<SampleHostedService> logger)
        {
            _logger = logger;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            _logger.LogInformation("Starting Hosted service");

            while (!stoppingToken.IsCancellationRequested)
            {
                _logger.LogInformation("Hosted service executing - {0}", DateTime.Now);
                await Task.Delay(TimeSpan.FromSeconds(2), stoppingToken);
            }
        }
    }
}

namespace MvcTest
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddHostedService<PrinterHostedService>();

D:\MvcTest>dotnet run
Hosting environment: Development
infoContent root path: D:\MvcTest
Now listening on: https://localhost:5001
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.
: MvcTest.SampleHostedService[0]
      Starting Hosted service
info: MvcTest.SampleHostedService[0]
      Hosted service executing - 02/19/2019 15:00:23
info: MvcTest.SampleHostedService[0]
      Hosted service executing - 02/19/2019 15:00:25
info: MvcTest.SampleHostedService[0]
      Hosted service executing - 02/19/2019 15:00:27
Application is shutting down...
^C

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

public abstract class ScopedBackgroundService : BackgroundService
{
    private readonly IServiceScopeFactory _serviceScopeFactory;

    public ScopedBackgroundService(IServiceScopeFactory serviceScopeFactory)
    {
        _serviceScopeFactory = serviceScopeFactory;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        using (var scope = _serviceScopeFactory.CreateScope())
        {
            await ExecuteInScope(scope.ServiceProvider, stoppingToken);
        }
    }

    public abstract Task ExecuteInScope(IServiceProvider serviceProvider, CancellationToken stoppingToken);
}

 dotnet add package ncrontab

┌───────────── minute (0 - 59) 
│ ┌───────────── hour (0 - 23) 
│ │ ┌───────────── day of month (1 - 31) 
│ │ │ ┌───────────── month (1 - 12) 
│ │ │ │ ┌───────────── day of week (0 - 6) (Sunday to Saturday; 
│ │ │ │ │                                       7 is also Sunday on some systems) 
│ │ │ │ │ 
│ │ │ │ │ 
* * * * *

* * * * * *
- - - - - -
| | | | | |
| | | | | +--- day of week (0 - 6) (Sunday=0)
| | | | +----- month (1 - 12)
| | | +------- day of month (1 - 31)
| | +--------- hour (0 - 23)
| +----------- min (0 - 59)
+------------- sec (0 - 59)

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using NCrontab;
using static NCrontab.CrontabSchedule;

public abstract class ScheduledScopedBackgroundService : ScopedBackgroundService
{
    private CrontabSchedule _schedule;
    private DateTime _nextRun;

    protected abstract string Schedule { get; }

    public ScheduledScopedBackgroundService(IServiceScopeFactory serviceScopeFactory)
     : base(serviceScopeFactory)
    {
        _schedule = CrontabSchedule.Parse(Schedule, new ParseOptions { IncludingSeconds = true });
        _nextRun = _schedule.GetNextOccurrence(DateTime.Now);
    }

    public override async Task ExecuteInScope(IServiceProvider serviceProvider, CancellationToken stoppingToken)
    {
        do
        {
            var now = DateTime.Now;
            if (now > _nextRun)
            {
                await ScheduledExecuteInScope(serviceProvider, stoppingToken);
                _nextRun = _schedule.GetNextOccurrence(DateTime.Now);
            }
            await Task.Delay(1000, stoppingToken); //1 second delay
        }
        while (!stoppingToken.IsCancellationRequested);
    }

    public abstract Task ScheduledExecuteInScope(IServiceProvider serviceProvider, CancellationToken stoppingToken);
}

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

public class MyScheduledTask : ScheduledScopedBackgroundService
{
    private readonly ILogger<MyScheduledTask> _logger;

    public MyScheduledTask(
        IServiceScopeFactory serviceScopeFactory,
        ILogger<MyScheduledTask> logger) : base(serviceScopeFactory)
    {
        _logger = logger;
    }

    protected override string Schedule => "*/10 * * * * *"; //Runs every 10 seconds

    public override Task ScheduledExecuteInScope(IServiceProvider serviceProvider, CancellationToken stoppingToken)
    {
        _logger.LogInformation("MyScheduledTask executing - {0}", DateTime.Now);
        return Task.CompletedTask;
    }
}

namespace MvcTest
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddHostedService<MyScheduledTask>();

D:\MvcTest>dotnet run
Hosting environment: Development
Content root path: D:\MvcTest
Now listening on: https://localhost:5001
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.
info: MyScheduledTask[0]
      MyScheduledTask executing - 02/19/2019 19:18:50
info: MyScheduledTask[0]
      MyScheduledTask executing - 02/19/2019 19:19:00
info: MyScheduledTask[0]
      MyScheduledTask executing - 02/19/2019 19:19:10
Application is shutting down...
^C

public class NumberedEntity : Entity, IMultiTenantEntity
{
    public string EntityName { get; set; }
    public long NextNumber { get; set; }
    
    public long TenantId { get; set; }
}

public class NumberedEntityConfiguration : IEntityTypeConfiguration<NumberedEntity>
{
    public void Configure(EntityTypeBuilder<NumberedEntity> builder)
    {
        builder.Property(a => a.EntityName).HasMaxLength(256).IsRequired().IsUnicode(false);
        builder.HasIndex(a => a.EntityName).HasName("UIX_NumberedEntity_EntityName").IsUnique();
        builder.ToTable(nameof(NumberedEntity));
    }
}

شاید به نظر، استفاده از این موجودیت ضروریتی نداشته باشد و خیلی راحت می‌توان آخرین شماره ثبت شده‌ی در جدول مورد نظر را واکشی، مقداری را به آن اضافه و به عنوان شماره منحصر به فرد رکورد جدید استفاده کرد؛ با این رویکرد حداقل دو مشکل زیر را خواهیم داشت:

• ایجاد Gap مابین شماره‌های تولید شده، که مدنظر ما نمی‌باشد. (با توجه به اینکه امکان ثبت دستی را هم داریم، ممکن است کاربر شماره‌ای را وارد کرده باشد که با آخرین شماره ثبت شده تعداد زیادی فاصله دارد که به خودی خود مشکل ساز نیست؛ ولی در زمان ثبت رکورد بعدی اگر به صورت خودکار ثبت شماره داشته باشد، قطعا آخرین شماره (بزرگترین) را که به صورت دستی وارد شده بود، از جدول دریافت خواهد کرد)

• مشکلات کارایی برای حل مسائل همزمانی

internal class NumberingPreInsertHook : PreInsertHook<INumberedEntity>
{
    private readonly IUnitOfWork _uow;
    private readonly IOptions<NumberingConfiguration> _configuration;

    public NumberingPreInsertHook(IUnitOfWork uow, IOptions<NumberingConfiguration> configuration)
    {
        _uow = uow ?? throw new ArgumentNullException(nameof(uow));
        _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
    }

    protected override void Hook(INumberedEntity entity, HookEntityMetadata metadata)
    {
        if (!entity.Number.IsNullOrEmpty()) return;

        bool retry;
        string nextNumber;
        
        do
        {
            nextNumber = GenerateNumber(entity);
            var exists = CheckDuplicateNumber(entity, nextNumber);
            retry = exists;
            
        } while (retry);
        
        entity.Number = nextNumber;
    }

    private bool CheckDuplicateNumber(INumberedEntity entity, string nextNumber)
    {
       //...
    }

    private string GenerateNumber(INumberedEntity entity)
    {
       //...
    }
}

ابتدا بررسی می‌شود اگر پراپرتی Number مقداردهی شده‌است، عملیات مقداردهی خودکار برروی آن انجام نگیرد. سپس با توجه به اینکه ممکن است به صورت دستی قبلا شماره‌ای مانند Task_1000 وارد شده باشد و NextNumber مرتبط هم مقدار 1000 را داشته باشد؛ در این صورت به هنگام ثبت رکورد بعدی، با توجه به Prefix تنظیم شده، دوباره به شماره Task_1000 خواهیم رسید که در این مورد خاص با استفاده از متد CheckDuplicateNumber این قضیه تشخیص داده شده و سعی مجددی برای تولید شماره جدید صورت می‌گیرد.

private string GenerateNumber(INumberedEntity entity)
{
    var option = _configuration.Value.NumberedEntityOptions[entity.GetType()];

    var entityName = $"{entity.GetType().FullName}";

    var lockKey = $"Tenant_{_uow.TenantId}_" + entityName;

    _uow.ObtainApplicationLevelDatabaseLock(lockKey);

    var nextNumber = option.Start.ToString();

    var numberedEntity = _uow.Set<NumberedEntity>().AsNoTracking().FirstOrDefault(a => a.EntityName == entityName);
    if (numberedEntity == null)
    {
        _uow.ExecuteSqlCommand(
            "INSERT INTO [dbo].[NumberedEntity]([EntityName], [NextNumber], [TenantId]) VALUES(@p0,@p1,@p2)", entityName,
            option.Start + option.IncrementBy, _uow.TenantId);
    }
    else
    {
        nextNumber = numberedEntity.NextNumber.ToString();
        _uow.ExecuteSqlCommand("UPDATE [dbo].[NumberedEntity] SET [NextNumber] = @p0 WHERE [Id] = @p1 ",
            numberedEntity.NextNumber + option.IncrementBy, numberedEntity.Id);
    }

    if (!string.IsNullOrEmpty(option.Prefix))
        nextNumber = option.Prefix + nextNumber;
    
    return nextNumber;
}

public static void ObtainApplicationLevelDatabaseLock(this IUnitOfWork uow, string resource)
{
    uow.ExecuteSqlCommand(@"EXEC sp_getapplock @Resource={0}, @LockOwner={1}, 
                @LockMode={2} , @LockTimeout={3};", resource, "Transaction", "Exclusive", 15000);
}

public class NumberingConfiguration
{
    public bool Enabled { get; set; }

    public IDictionary<Type, NumberedEntityOption> NumberedEntityOptions { get; } =
        new Dictionary<Type, NumberedEntityOption>();
}

public class NumberedEntityOption
{
    public string Prefix { get; set; }
    public int Start { get; set; } = 1;
    public int IncrementBy { get; set; } = 1;
}

public static void AddNumbering(this IServiceCollection services,
    IDictionary<Type, NumberedEntityOption> options)
{
    services.Configure<NumberingConfiguration>(configuration =>
    {
        configuration.Enabled = true;
        configuration.NumberedEntityOptions.AddRange(options);
    });
    
    services.AddTransient<IPreActionHook, NumberingPreInsertHook>();
}

services.AddNumbering(new Dictionary<Type, NumberedEntityOption>
{
    [typeof(Task)] = new NumberedEntityOption
    {
        Prefix = "T_",
        Start = 1000,
        IncrementBy = 5
    }
});

public class Task : TrackableEntity, IAggregateRoot, INumberedEntity
{
    public const int MaxTitleLength = 256;
    public const int MaxDescriptionLength = 1024; 

    public string Title { get; set; }
    public string NormalizedTitle { get; set; }
    public string Description { get; set; }
    public TaskState State { get; set; } = TaskState.Todo; 
    public byte[] RowVersion { get; set; }
    public string Number { get; set; }
}

    var ms = new MemoryStream();
    using (var writer = XmlWriter.Create(ms))
    {
        EdmxWriter.WriteEdmx(new Context(), writer);
    }

    var xDoc = XDocument.Load(ms);

    var ssdl = xDoc.Descendants("{http://schemas.microsoft.com/ado/2009/02/edm/ssdl}Schema").Single();
    var csdl = xDoc.Descendants("{http://schemas.microsoft.com/ado/2008/09/edm}Schema").Single();
    var msl = xDoc.Descendants("{http://schemas.microsoft.com/ado/2008/09/mapping/cs}Mapping").Single();

 EdmGen.exe /mode:ViewGeneration /incsdl:Context.csdl  /inmsl:Context.msl /inssdl:Context.ssdl /outviews:Context.Views.cs

using System;
using System.Data.Entity;
using System.Data.Entity.Design;
using System.Data.Entity.Infrastructure;
using System.Data.Mapping;
using System.Data.Metadata.Edm;
using System.IO;
using System.Linq;
using System.Xml;
using System.Xml.Linq;

namespace EfUtils
{
    public static class PreGeneratedViewsWriter
    {
        public static void CreatePreGeneratedViewsFile(
                this DbContext contextInstance,
                LanguageOption language = LanguageOption.GenerateCSharpCode,
                string viewsFile = "Context.Views.cs",
                string edmxFile = "context.edmx",
                string ssdlFile = "context.ssdl.xml",
                string csdlFile = "context.csdl.xml",
                string mslFile = "context.msl.xml")
        {
            using (var contextViewsMemoryStream = new MemoryStream())
            {
                using (var edmxMemoryStream = new MemoryStream())
                {
                    var edmx = createEdmx(contextInstance, edmxFile, edmxMemoryStream);
                    var mappingItemCollection = createMappingItemCollection(ssdlFile, csdlFile, mslFile, edmx);
                    generateViews(language, viewsFile, contextViewsMemoryStream, mappingItemCollection);
                }
            }
        }

        private static void generateViews(LanguageOption language, string viewsFile, MemoryStream contextViewsMemoryStream, StorageMappingItemCollection mappingItemCollection)
        {
            var viewGenerator = new EntityViewGenerator // It's defined in System.Data.Entity.Design.dll
            {
                LanguageOption = language
            };
            using (var streamWriter = new StreamWriter(contextViewsMemoryStream))
            {
                var errors = viewGenerator.GenerateViews(mappingItemCollection, streamWriter).ToList();

                if (errors.Any())
                    throw new InvalidOperationException(errors.First().Message);

                contextViewsMemoryStream.Position = 0;
                using (var reader = new StreamReader(contextViewsMemoryStream))
                {
                    var codeData = reader.ReadToEnd();
                    File.WriteAllText(viewsFile, codeData);
                }
            }
        }

        private static StorageMappingItemCollection createMappingItemCollection(string ssdlFile, string csdlFile, string mslFile, XDocument edmx)
        {
            var ssdl = edmx.Descendants("{http://schemas.microsoft.com/ado/2009/02/edm/ssdl}Schema").Single();
            ssdl.Save(ssdlFile);
            var storeItemCollection = new StoreItemCollection(new[] { ssdl.CreateReader() });

            var csdl = edmx.Descendants("{http://schemas.microsoft.com/ado/2008/09/edm}Schema").Single();
            csdl.Save(csdlFile);
            var edmItemCollection = new EdmItemCollection(new[] { csdl.CreateReader() });

            var msl = edmx.Descendants("{http://schemas.microsoft.com/ado/2008/09/mapping/cs}Mapping").Single();
            msl.Save(mslFile);

            var mappingItemCollection = new StorageMappingItemCollection(edmItemCollection, storeItemCollection, new[] { msl.CreateReader() });
            return mappingItemCollection;
        }

        private static XDocument createEdmx(DbContext contextInstance, string edmxFile, MemoryStream edmxMemoryStream)
        {
            var settings = new XmlWriterSettings { Indent = true };
            using (var writer = XmlWriter.Create(edmxMemoryStream, settings))
            {
                EdmxWriter.WriteEdmx(contextInstance, writer);
            }
            File.WriteAllBytes(edmxFile, edmxMemoryStream.ToArray());

            edmxMemoryStream.Position = 0;
            var edmx = XDocument.Load(edmxMemoryStream);
            return edmx;
        }
    }
}

 Database.SetInitializer<MyContext>(null);

export class PagedQueryModel {
  constructor(
    // ...
    public filterByColumn: string,
    public filterByValue: string,
  ) { }
}

  doFilter() {
    this.queryModel.page = 1;
    this.getPagedProductsList();
  }

  resetFilter() {
    this.queryModel.page = 1;
    this.queryModel.filterByColumn = "";
    this.queryModel.filterByValue = "";
    this.getPagedProductsList();
  }

<div class="panel panel-default">
  <div class="panel-body">
    <div class="form-group">
      <input type="text" [(ngModel)]="queryModel.filterByValue" placeholder="Search For ..."
        class="form-control" />
    </div>
    <div class="form-group">
      <select class="form-control" name="filterColumn" [(ngModel)]="queryModel.filterByColumn">
        <option value="">Filter by ...</option>
        <option *ngFor="let column of columns" [value]="column.propertyName">
          {{ column.title }}
        </option>
      </select>
    </div>
    <button class="btn btn-primary" type="button" (click)="doFilter()">Search</button>
    <button class="btn btn-default" type="button" (click)="resetFilter()">Reset</button>
  </div>
</div>

    public interface IPagedQueryModel
    {
    // ....
        string FilterByColumn { get; set; }
        string FilterByValue { get; set; }
    }

    public class ProductQueryViewModel : IPagedQueryModel
    {
        // ... other properties ...

// ...
        public string FilterByColumn { get; set; }
        public string FilterByValue { get; set; }
    }

    public static class IQueryableExtensions
    {
        public static IQueryable<T> ApplyFiltering<T>(
          this IQueryable<T> query,
          IPagedQueryModel model,
          IDictionary<string, Expression<Func<T, object>>> columnsMap)
        {
            if (string.IsNullOrWhiteSpace(model.FilterByValue) || !columnsMap.ContainsKey(model.FilterByColumn))
            {
                return query;
            }

            var func = columnsMap[model.FilterByColumn].Compile();
            return query.Where(x => func(x).ToString() == model.FilterByValue);
        }

var columnsMap = new Dictionary<string, Expression<Func<Product, object>>>()
            {
                ["productId"] = p => p.ProductId,
                ["productName"] = p => p.ProductName,
                ["isAvailable"] = p => p.IsAvailable,
                ["price"] = p => p.Price
            };
query = query.ApplyFiltering(queryModel, columnsMap);
query = query.ApplyOrdering(queryModel, columnsMap);