Asp.net 5 and MVC 6

Asp.net 5 was completely written from scratch. So by changing the name (Asp.net 5) and picking a better version number introduced ASP.NET CORE 1.0 AND .NET CORE 1.0.

  ~ASP.NET 5 is now ASP.NET Core 1.0.
  ~.NET Core 5 is now .NET Core 1.0.
  ~Entity Framework 7 is now Entity Framework Core 1.0 or EF Core 1.0 colloquially.

 Why 1.0? Because these are new. The whole .NET Core concept is new. The .NET Core 1.0 CLI is very new. Not only that, but .NET Core isn't as complete as the full .NET Framework 4.6. it is still imroving. The microsoft team still exploring gaps between ASP.NET 4.6 and ASP.NET Core 1.0.

WHICH TO CHOOSE?

To be clear, ASP.NET 4.6 is the more mature platform. It's battle-tested and released and available today. ASP.NET Core 1.0 is a 1.0 release that includes Web API and MVC but doesn't yet have SignalR or Web Pages. It doesn't yet support VB or F#. It will have these subsystems some day but not today.

We don't want anyone to think that ASP.NET Core 1.0 is the finish line. It's a new beginning and a fork in the road, but ASP.NET 4.6 continues on, released and fully supported. There's lots of great stuff coming, stay tuned!

Reference: http://www.hanselman.com/blog/ASPNET5IsDeadIntroducingASPNETCore10AndNETCore10.aspx

Top 10 Changes in ASP.NET 5 or Asp.net Core 1.0 and MVC 6
1. ASP.NET on OSX and Linux
For the first time in the history of ASP.NET, you can run ASP.NET 5 applications on OSX and Linux.

2. No More Web Forms
ASP.NET Web Forms is not part of ASP.NET 5.

3. No More Visual Basic
ASP.NET 5 only supports C# and Visual Basic is left behind.

4. Tag Helpers

Tag Helpers is the one feature that might have the biggest impact on the way that you create your views in an ASP.NET MVC application. Tag Helpers are a better alternative to using traditional MVC helpers. Consider the following MVC view that contains a form for creating a new product:

@using (Html.BeginForm()) => 

  @Html.TextBoxFor(m => p.Name) =>  < input asp-for="Name" / >

In the view above, the Html.BeginForm(), Html.LabelFor(), and Html.TextBoxFor() helpers are used to create the form. These helpers would not be familiar to an HTML designer.

The only thing special about this view is the special asp-for attributes. These attributes are used to extend the elements with server-side ASP.NET MVC functionality.

5. View Components
Subcontrollers – the Html.Action() helper — are not included in the current beta of MVC 6. Instead, MVC 6 includes an alternative technology called View Components.
Here’s how you can create a View Component that displays one of two banner advertisements depending on the time of day:

using Microsoft.AspNet.Mvc;
using System;

namespace Partials.Components
{
    public class BannerAd : ViewComponent
    {
        public IViewComponentResult Invoke()
        {
            var adText = "Buy more coffee!";

            if (DateTime.Now.Hour > 18)
            {
                adText = "Buy more warm milk!";
            }
            return View("_Advertisement", adText);
        }
    }
}

6. GruntJS, NPM, and Bower Support
Front-end development gets a lot of love in ASP.NET 5 through its support for GruntJS (and eventually Gulp).

GruntJS is a task runner that enables you to build front-end resources such as JavaScript and CSS files. For example, you can use GruntJS to concatenate and minify your JavaScript files whenever you perform a build in Visual Studio.

In order to support GruntJS, Microsoft needed to support two new package managers (beyond NuGet). First, because GruntJS plugins are distributed as NPM packages, Microsoft added support for NPM packages.
Second, because many client-side resources – such as Twitter Bootstrap, jQuery, Polymer, and AngularJS – are distributed through Bower, Microsoft added support for Bower.
This means that you can run GruntJS using plugins from NPM and client resources from Bower.

7. Unified MVC and Web API Controllers
In previous versions of ASP.NET MVC, an MVC controller used the System.Web.MVC.Controller base class and a Web API controller used the System.Web.Http.ApiController base class.

In MVC 6, there is one and only one Controller class that is the base class for both MVC and Web API controllers. There is only the Microsoft.AspNet.Mvc.Controller class.

8. AngularJS
Visual Studio 2015 includes templates for creating AngularJS modules, controllers, directives, and factories.The support in ASP.NET 5 for GruntJS makes ASP.NET an excellent server-side framework for building client-side AngularJS apps.You can interact with an MVC 6 controller from an AngularJS $resource using REST.

9. ASP.NET Dependency Injection Framework
ASP.NET 5 has built-in support for Dependency Injection and the Service Locator pattern. This means that you no longer need to rely on third-party Dependency Injection frameworks such as Ninject or AutoFac.

10. xUnit.net
In previous versions of ASP.NET MVC, the default testing framework was the Visual Studio Unit Testing Framework (sometimes called mstest). This framework uses the [TestClass] and [TestMethod] attributes to describe a unit test:

ASP.NET 5 uses xUnit.net as its unit test framework. This framework uses the [Fact] attribute instead of the [TestMethod] attribute (and no [TestClass] attribute]):


Reference : http://stephenwalther.com/archive/2015/02/24/top-10-changes-in-asp-net-5-and-mvc-6