var searchModel = new Pupil
{
    FirstName = "Ben",
    LastName = null,
    City = null,
    PostalZipCode = null
};

List<Pupil> pupils = db.Pupils.Where(p =>
        (searchModel.FirstName == null || p.FirstName == searchModel.FirstName)
        && (searchModel.LastName == null || p.LastName == searchModel.LastName)
        && (searchModel.City == null || p.LastName == searchModel.City)
        && (searchModel.PostalZipCode == null || p.PostalZipCode == searchModel.PostalZipCode))
    .Take(100)
    .ToList()

 USE [EFSchoolSystem]
DECLARE @p__linq__0 NVarChar(4000) SET @p__linq__0 = 'Ben'
DECLARE @p__linq__1 NVarChar(4000) SET @p__linq__1 = 'Ben'
DECLARE @p__linq__2 NVarChar(4000) SET @p__linq__2 = ''
DECLARE @p__linq__3 NVarChar(4000) SET @p__linq__3 = ''
DECLARE @p__linq__4 NVarChar(4000) SET @p__linq__4 = ''
DECLARE @p__linq__5 NVarChar(4000) SET @p__linq__5 = ''
DECLARE @p__linq__6 NVarChar(4000) SET @p__linq__6 = ''
DECLARE @p__linq__7 NVarChar(4000) SET @p__linq__7 = ''

-- Executed query
SELECT TOP (100)
        [Extent1].[PupilId] AS [PupilId] ,
        [Extent1].[FirstName] AS [FirstName] ,
        [Extent1].[LastName] AS [LastName] ,
        [Extent1].[Address1] AS [Address1] ,
        [Extent1].[Adderss2] AS [Adderss2] ,
        [Extent1].[PostalZipCode] AS [PostalZipCode] ,
        [Extent1].[City] AS [City] ,
        [Extent1].[PhoneNumber] AS [PhoneNumber] ,
        [Extent1].[SchoolId] AS [SchoolId] ,
        [Extent1].[Picture] AS [Picture]
FROM    [dbo].[Pupils] AS [Extent1]
WHERE   (@p__linq__0 IS NULL OR [Extent1].[FirstName] = @p__linq__1)
        AND (@p__linq__2 IS NULL OR [Extent1].[LastName] = @p__linq__3)
        AND (@p__linq__4 IS NULL OR [Extent1].[LastName] = @p__linq__5)
        AND (@p__linq__6 IS NULL OR [Extent1].[PostalZipCode] = @p__linq__7)

 if (searchModel.City == null)
{
    pupils = db.Pupils.Where(p =>
        (searchModel.FirstName == null || p.FirstName == searchModel.FirstName)
        && (searchModel.LastName == null || p.LastName == searchModel.LastName)
        && (searchModel.PostalZipCode == null || p.PostalZipCode == searchModel.PostalZipCode))
        .Take(100)
        .ToList();
}
else
{
    pupils = db.Pupils.Where(p =>
        (searchModel.FirstName == null || p.FirstName == searchModel.FirstName)
        && (searchModel.LastName == null || p.LastName == searchModel.LastName)
        && (searchModel.City == null || p.LastName == searchModel.City)
        && (searchModel.PostalZipCode == null || p.PostalZipCode == searchModel.PostalZipCode))
        .Take(100)
        .ToList();
}

public class RecompileDbCommandInterceptor : IDbCommandInterceptor
{
    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        if(!command.CommandText.EndsWith(" option(recompile)"))
        {
            command.CommandText += " option(recompile)";
        }
    }
    //and implement other interface members
}

 var interceptor = new RecompileDbCommandInterceptor();
DbInterception.Add(interceptor);
var pupils = db.Pupils.Where(p => p.City = city).ToList();
DbInterception.Remove(interceptor);

var result = db.Pupils.AsQueryable();

if(searchModel.FirstName != null )
     result = result.Where(p => p.FirstName == searchModel.FirstName);

if(searchModel.LastName != null )
     result = result.Where(p => p.LastName == searchModel.LastName);

if(searchModel.PostalZipCode != null )
     result = result.Where(p => p.PostalZipCode == searchModel.PostalZipCode);

if(searchModel.City != null )
     result = result.Where(p => p.City == searchModel.City);

var schools = db.Schools
    .OrderBy(s => s.PostalZipCode)
    .Skip(model.Page * model.ResultsPerPage)
    .Take(model.ResultsPerPage)
    .ToList();

SELECT  text, query_plan
FROM    sys.dm_exec_cached_plans
        CROSS APPLY sys.dm_exec_query_plan(plan_handle)
        CROSS APPLY sys.dm_exec_sql_text(plan_handle)

int resultsToSkip = model.Page * model.ResultsPerPage;
var schools = db.Schools
    .OrderBy(s => s.PostalZipCode)
    .Skip(() => resultsToSkip) //must pre-calculate this value
    .Take(() => model.ResultsPerPage)
    .ToList();

CREATE TABLE app_product (
     Id Int IDENTITY NOT NULL,
     Description_en Text,
     Description_pl Text,
     PRIMARY KEY (Id)
);

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>

 PM> install-package Newtonsoft.Json

 var roles = new List<string>
{
   "Admin",
   "User"
};
string json = JsonConvert.SerializeObject(roles, Formatting.Indented);

 var jsonString = JsonConvert.SerializeObject(new
{
   Id =1,
   Name = "Test"
}, Formatting.Indented);

var jsonData = JsonConvert.SerializeObject(new
{
   Id = 1,
   Name = "Test",
   DateTime = DateTime.Now
}, new JsonSerializerSettings
{
   Formatting = Formatting.Indented,
   Converters =
   {
      new JavaScriptDateTimeConverter()
   }
});

 {
  "Id": 1,
  "Name": "Test",
  "DateTime": new Date(1409821985245)
}

using (var stream = File.CreateText(@"c:\output.json"))
{
    var jsonSerializer = new JsonSerializer
   {
      Formatting = Formatting.Indented
   };
   jsonSerializer.Serialize(stream, new
   {
     Id = 1,
     Name = "Test",
     DateTime = DateTime.Now
   });
}

public class User
{
   public int Id { set; get; }
   public string Name { set; get; }
   public DateTime DateTime { set; get; }
}

 var user = JsonConvert.DeserializeObject<User>(jsonData);

var user = JsonConvert.DeserializeObject<User>(jsonData, new JsonSerializerSettings
{
   Converters = {  new JavaScriptDateTimeConverter() }
});

 JsonConvert.PopulateObject(jsonData, user);

var jsonData = JsonConvert.SerializeObject(object, new JsonSerializerSettings
{
   NullValueHandling = NullValueHandling.Ignore,
   Formatting = Formatting.Indented
});

public class Employee
{
    public string Name { set; get; }
}

public class Manager : Employee
{
    public IList<Employee> Reports { set; get; }
}

 var employee = new Employee { Name = "User1" };
var manager1 = new Manager { Name = "User2" };
var manager2 = new Manager { Name = "User3" };
manager1.Reports = new[] { employee, manager2 };
manager2.Reports = new[] { employee };

 var list = JsonConvert.SerializeObject(manager1, Formatting.Indented);

{
  "Reports": [
    {
      "Name": "User1"
    },
    {
      "Reports": [
        {
          "Name": "User1"
        }
      ],
      "Name": "User3"
    }
  ],
  "Name": "User2"
}

var list = JsonConvert.SerializeObject(manager1, new JsonSerializerSettings
{
   Formatting = Formatting.Indented,
   TypeNameHandling = TypeNameHandling.Objects,
   PreserveReferencesHandling = PreserveReferencesHandling.Objects
});
 

{
  "$id": "1",
  "$type": "JsonNetTests.Manager, JsonNetTests",
  "Reports": [
    {
      "$id": "2",
      "$type": "JsonNetTests.Employee, JsonNetTests",
      "Name": "User1"
    },
    {
      "$id": "3",
      "$type": "JsonNetTests.Manager, JsonNetTests",
      "Reports": [
        {
          "$ref": "2"
        }
      ],
      "Name": "User3"
    }
  ],
  "Name": "User2"
}

public class User
{
   public int Id { set; get; }

   [JsonIgnore]
   public string Name { set; get; }

   public DateTime DateTime { set; get; }
}

[JsonProperty(PropertyName = "m_name", NullValueHandling = NullValueHandling.Ignore)]
public string Name { set; get; }

[JsonObject(MemberSerialization.OptIn)]
public class User
{
    public int Id { set; get; }

    [JsonProperty]
    public string Name { set; get; }
 
    public DateTime DateTime { set; get; }
}

[JsonConverter(typeof(JavaScriptDateTimeConverter))]
public DateTime DateTime { set; get; }

public class HtmlColor
{
   public int Red { set; get; }
   public int Green { set; get; }
   public int Blue { set; get; }
}

var colorJson = JsonConvert.SerializeObject(new HtmlColor
{
  Red = 255,
  Green = 0,
  Blue = 0
}, Formatting.Indented);

    public class HtmlColorConverter : JsonConverter
    {

        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(HtmlColor);
        }

        public override object ReadJson(JsonReader reader, Type objectType,
                                        object existingValue, JsonSerializer serializer)
        {
            throw new NotSupportedException();
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            var color = value as HtmlColor;
            if (color == null)
                return;

            writer.WriteValue("#" + color.Red.ToString("X2")
                + color.Green.ToString("X2") + color.Blue.ToString("X2"));
        }
    }

var colorJson = JsonConvert.SerializeObject(new HtmlColor
{
  Red = 255,
  Green = 0,
  Blue = 0
},  new JsonSerializerSettings
    {
      Formatting = Formatting.Indented,
      Converters = { new HtmlColorConverter() }
    });   

It's like JSON. but fast and small.

MessagePack is supported by over 50 programming languages and environments. 

//C#
// Creates serializer.
var serializer = SerializationContext.Default.GetSerializer<T>();

// Pack obj to stream.
serializer.Pack(stream, obj);

// Unpack from stream.
var unpackedObject = serializer.Unpack(stream);

            return new PdfReport().DocumentPreferences(doc =>
            {
                // ...
                doc.Compression(new CompressionSettings
                {
                    EnableCompression = true,
                    EnableFullCompression = true
                });
            })