• We added support to change installation locations.
• You can Save All your pending changes before you start your update.
• The update dialog provides you even more details about your update during installation.
• C# 7.3 is included in Visual Studio version 15.7.
• We improved solution load time for C# and VB projects.
• We made numerous updates to F# and its tools, with a focus on performance.
• We reduced the time to enable IntelliSense for large .NET Core projects by 25%.
• We made Quick Info improvements and new .NET refactorings like convert for-to-foreach and make private fields readonly.
• We added the ability to publish ASP.NET Core applications to App Service Linux without containers.
• Live Unit Testing works with embedded pdbs and supports projects that use reference assemblies.
• The Test Explorer has more responsive icons during test runs.
• C++ developers can use CodeLens for unit testing.
• We added new rules enforcing items from the C++ Core Guidelines.
• Debugging large solutions with /Debug:fastlink PDBs is more robust.
• CMake integration supports CMake 3.11 and static analysis.
• Python projects support type hints in IntelliSense, and a Run MyPy command has been added to look for typing errors in your code.
• Conda environments are supported in Python projects.
• We added a next version of our Python debugger based on the popular open source pydevd debugger.
• TypeScript 2.8 is included in Visual Studio version 15.7.
• We improved Kestrel HTTPs support during debugging.
• We added support for JavaScript debugging with Microsoft Edge.
• The Debugger supports VSTS and GitHub Authentication for Source Link.
• IntelliTrace’s step-back debugging feature is supported for debugging .NET Core projects.
• We added IntelliTrace support for taking snapshots on exceptions.
• We removed the blocking modal dialog from branch checkouts in Git when a solution or project reload is not required.
• There is an option to choose between OpenSSL and SChannel in Git.
• You can create and associate Azure Key Vaults from within the Visual Studio IDE.
• Visual Studio Tools for Xamarin can automatically install missing Android API levels required by Xamarin.Android projects.
• The Xamarin.Forms XAML editor provides IntelliSense and quick fixes for conditional XAML.
• We added support for Azure, UWP, and additional project types in Visual Studio Build Tools.
• You can create build servers without installing all of Visual Studio.
• The Windows 10 April 2018 Update SDK - Build 17134 is the default required SDK for the Universal Windows Platform development workload.
• We added support for Visual State Management for all UWP apps and more.
• We enabled automatic updates for sideloaded APPX packages.
• You have new tools for migrating to NuGet PackageReference.
• We added support for NuGet package signatures.
• We added Service Fabric Tooling for the 6.2 Service Fabric release.
• We updated Entity Framework Tools to work with the EF 6.2 runtime and to improve reverse engineering of existing databases.

Choosing the right framework for your projects is a daunting task and can affect the completion of the project in stipulated time period. Five widely used frameworks- AngularJS, ReactJs, Knockout, Backbone and Ember give an option along with putting your knowledge to test to make a smart choice.  

public class ContactVM
    {
        [Display(Name = "نام")]
        [Required(ErrorMessage = "لطفا {0} را وارد کنید")]
        public string Name { get; set; }

              [EmailAddress(ErrorMessage = "آدرس ایمیل صحیح نیست")]
        [DataType(DataType.EmailAddress)]
        [Display(Name = "آدرس ایمیل")]
        [Required(ErrorMessage = "لطفا {0} را وارد کنید")]
        public string EmailAddress { get; set; }

        [Display(Name = "متن پیام")]
        [Required(ErrorMessage = "حرفی برای گفتن ندارید؟")]
        public string Description { get; set; }

        [Required(ErrorMessage = "لطفا {0} را وارد کنید")]
        [Display(Name = "حاصل جمع")]
        public string Captcha { get; set; }
    }

    public class SubscriberVM
    {   
        /*[RegularExpression("^[a-zA-Z0-9_\\.-]+@([a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,6}$", ErrorMessage = "آدرس ایمیل صحیح نیست")]*/
          [EmailAddress(ErrorMessage = "آدرس ایمیل صحیح نیست")] /*.Net4.5*/
        [Display(Name = "ایمیل")]
        [Required(ErrorMessage = "لطفا {0} را وارد کنید")]
        public string Email { get; set; }

        [Display(Name = "وضعیت")]
        public bool IsActive { get; set; }    
    }

        <div class="row footerclass">
            <div class="col-md--6">
                @Html.Action("Subscribers", "Home")
            </div>
            <div class="col-md-6">
                @Html.Action("Contact", "Home")
            </div>

        </div>

public ActionResult Contact()
        {
            return PartialView("_Contact", model);
        }

        [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]

        public ActionResult Contact(ContactVM model)
        {
              if (ModelState.IsValid)
                {
//Do Something                    
                }
            return PartialView("_Contact", model);
        }

        public ActionResult Subscribers()
        {
            return PartialView("_Subscribers");
        }

        [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
        public ActionResult Subscribers(SubscriberVM model)
        {
                if (ModelState.IsValid)
                {
//Do Something
                }
            }
            return PartialView("_Subscribers",model);
        }

@model IrsaShop.Models.ViewModel.ContactVM


<span></span><span>تماس با ما</span>
<hr />

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)
    <div>
        @Html.TextBoxFor(m => m.Name, new { @class = "form-control", @id = "name", @name = "name", placeholder = "نام" })
        @Html.ValidationMessageFor(m => m.Name)
    </div>
    <div>
        @Html.TextBoxFor(m => m.EmailAddress, new { @class = "form-control", @id = "email", @name = "email", placeholder = "ایمیل", @style = "direction: ltr" })
        @Html.ValidationMessageFor(m => m.EmailAddress)
    </div>
    <div>
        @Html.TextAreaFor(model => model.Description, new { @class = "form-control", @id = "message", @name = "message", placeholder = "پیام", @style = "max-width: 100%;height: 90px;" })
    </div>
    <div>
        <input type="button" value="" id="refresh" />
        <img alt="Captcha" id="imgcpatcha" src="@Url.Action("CaptchaImage","Captcha")" />
    </div>
    <div>
        @Html.TextBoxFor(model => model.Captcha, new { @class = "form-control", placeholder = "حاصل جمع؟" })
        @Html.ValidationMessageFor(model => model.Captcha)

    </div>
    <div>
        <input type="submit" value="ارسال" name="submitValue" />
    </div>
}

@model IrsaShop.Models.SubscriberVM

<span></span><span>خبرنامه</span>
<hr/>

@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
    @Html.ValidationSummary(true)
    <div>

        <div>
            @Html.TextBoxFor(m => m.Email, new { @class = "form-control right-buffer top-buffer pull-right", @id = "email", @name = "email", placeholder = "ایمیل", @style = "direction: ltr;width: 50%", @required = "required" })
       @*     <button type="submit" name="submitValue">ثبت ایمیل</button>*@
            <input type="submit" value="ثبت ایمیل" name="submitValue" />
        </div>
        
    </div>
   @Html.ValidationMessageFor(m => m.Email,"",new { @class = "right-buffer pull-right"})
   
}

        [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]

        public ActionResult Contact(ContactVM model, , string submitValue)
        {
   if (submitValue == "ارسال") 
                {
                 if (ModelState.IsValid)
                {
//Do Something                    
                }
}   else
                {
                         ModelState.Clear();
                }        
            return PartialView("_Subscribers", model);
        }

        [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
public ActionResult Subscribers(SubscriberVM model, string submitValue)
        {
             if (submitValue == "ثبت ایمیل") 
            {
if (ModelState.IsValid)
                {
//Do Something
                }
}
            else
            {
                ModelState.Clear();
            }
            return PartialView("_Subscribers");
        }

[HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
        public ActionResult Subscribers(SubscriberVM model, string submitValue)
        {
            if (submitValue == "ثبت ایمیل")
            {                
                if (ModelState.IsValid)
                {
                    Subscriber mail = new Subscriber() { Email = model.EmailSubscriber, IsActive = true };
                    context.Subscribers.Add(mail);
                    context.SaveChanges();
                    ViewBag.info = "ایمیل شما با موفقیت ثبت شد.";
                    ViewBag.color = "alert-success";
                    ModelState.Clear();
                }
            }
            else
            {
                ModelState.Clear();
            }
            
            return PartialView("_Subscribers ");
        }

@if (!String.IsNullOrEmpty(ViewBag.info))
{
    <div id="info" style="position: fixed; bottom: 0; right: 0; margin-right: 1%;">

        <div class="alert @ViewBag.color alert-dismissable">
            <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
            <strong> @ViewBag.info</strong>
        </div>

    </div>
    <script>
        $(function () {
            $("#info").fadeOut(15000);
        });
    </script>
}

• یکی از محدودیت‌های استفاده از expression body داشتن چندین خط دستور برای بدنه متدهایمان است. در اینحالت باید از روش سابق (statement body) استفاده نمائید. 
• یکی دیگر از محدودیت‌ها عدم امکان استفاده از if, else, switch است. به عنوان مثال نمی‌توان کد زیر را با داشتن if و else به صورت expression body نوشت:

public override string ToString() =>
                    (MiddleName != null)
                    ? FirstName + " " + MiddleName + " " + LastName
                    : FirstName + " " + LastName;

• همچنین نمی‌توان از for, foreach, while, do در expression body استفاده کرد، به جای آن می‌توان از عبارت‌های LINQ برای بدنه تابع استفاده کرد. به عنوان مثال متد زیر:
  

public IEnumerable<int> SmallNumbers() => Enumerable.Range(0, 10).Select(n => n);

• همانطور که عنوان شد، استفاده از expression body در قسمت پراپرتی‌ها تنها محدود به پراپرتی‌های get-only (فقط خواندنی) میباشد.
  
• استفاده از این قابلیت برای متدهای سازنده
• استفاده در رخدادها
• استفاده در finalizers

    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }

        public Person()
        {
            this.FirstName = "Sirwan";
            this.LastName = "Afifi";
        }
    }

public string FirstName { get; set; } = "Sirwan";
public string LastName { get; set; } = "Afifi";

public interface IAuthentication
{
    bool IsUserAuthenticated(string userName, string password);
}

public class AuthenticationService : IAuthentication
{
    public bool IsUserAuthenticated(string userName, string password)
    {
        return userName == "Vahid" && password == "123";
    }
}

public class LoginController
{
    private readonly IAuthentication _authentication;
    public LoginController(IAuthentication authentication)
    {
        _authentication = authentication;
    }

    // ...
}

Mads takes a whirlwind tour through the language features in the upcoming C# 11. Static virtual members, list patterns, required properties and raw string literals are all among the new tools in your toolbox for writing cleaner, safer, more general and more concise code in C#. 

The some() and every() Array Methods in JavaScript 

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.ActionConstraints;
using Microsoft.AspNetCore.Routing;

namespace WebToolkit
{
    public static class AjaxExtensions
    {
        private const string RequestedWithHeader = "X-Requested-With";
        private const string XmlHttpRequest = "XMLHttpRequest";

        public static bool IsAjaxRequest(this HttpRequest request)
        {
            return request?.Headers != null && request.Headers[RequestedWithHeader] == XmlHttpRequest;
        }
    }

    public class AjaxOnlyAttribute : ActionMethodSelectorAttribute
    {
        public override bool IsValidForRequest(RouteContext routeContext, ActionDescriptor action)
        {
            return routeContext.HttpContext.Request.IsAjaxRequest();
        }
    }
}