Use Roslyn to Write a Live Code Analyzer for Your API 

PTVS offers an advanced IDE experience for general scripting, web programming, and technical computing. 

Here’s what’s new in this preview release:

• .NET Hot Reload updates for dotnet watch
• ASP.NET Core SPA templates updated to Angular 11 and React 17
• Use Razor syntax in SVG foreignObject elements
• Specify null for Action and RenderFragment component parameters
• Reduced Blazor WebAssembly download size with runtime relinking
• Configurable buffer threshold before writing to disk in Json.NET output formatter
• Subcategories for better filtering of Kestrel logs
• Faster get and set for HTTP headers
• Configurable unconsumed incoming buffer size for IIS 

Sublime Text plugin for performing quick inline calculations with a simple keypress (Alt+C)

using System.Collections.Generic;

namespace TestRouting.Models
{
    public class Issue
    {
        public int IssueId { set; get; }
        public int ProjectId { set; get; }
        public string Title { set; get; }
        public string Body { set; get; }
    }

    public static class IssuesDataSource
    {
        public static IList<Issue> CreateDataSource()
        {
            var results = new List<Issue>();
            for (int i = 0; i < 100; i++)
            {
                results.Add(new Issue { IssueId = i, ProjectId = i, Body = "Test...", Title = "Title " + i });
            }
            return results;
        }
    }
}

using System.Linq;
using System.Web.Mvc;
using TestRouting.Models;

namespace TestRouting.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            var issuesList = IssuesDataSource.CreateDataSource();
            return View(issuesList); //show the list
        }

        public ActionResult Details(int issueId, int projectId)
        {
            var issue = IssuesDataSource.CreateDataSource()
                                        .Where(x => x.IssueId == issueId && x.ProjectId == projectId)
                                        .FirstOrDefault();
            return View(issue);
        }
    }
}

@model IEnumerable<TestRouting.Models.Issue>
@{
    ViewBag.Title = "Index";
}
<h2>
    Issues</h2>
<ul>
    @foreach (var item in Model)
    {
   
        <li>
            @Html.ActionLink(linkText: item.Title,
                     actionName: "Details",
                     controllerName: "Home",
                     routeValues: new { issueId = item.IssueId, projectId = item.ProjectId },
                     htmlAttributes: null)
        </li>
    }
</ul>

 http://localhost:1036/Home/Details?issueId=0&projectId=0

 http://localhost:1036/Home/Details/0/0

using System.Web.Mvc;
using System.Web.Routing;

namespace TestRouting
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "IssueDetails",
                url: "Details/{issueId}/{projectId}", //تطابق با یک چنین مسیرهایی
                defaults: new 
                          { 
                                controller = "Home", //کنترلری که این نوع مسیرها را پردازش خواهد کرد
                                action = "Details", // اکشن متدی که نهایتا پارامترها را دریافت می‌کند
                                issueId = UrlParameter.Optional, //این خواص نیاز است هم نام پارامترهای اکشن متد تعریف شوند
                                projectId = UrlParameter.Optional
                          }
            );

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
            );
        }
    }
}

 http://localhost:1036/Home/Details/0/0

01 - The Basics
02 - TreeViews and Value Converters
03 - View Model MVVM Basics
04 - Custom Window Chrome and Styles
05 - Creating Login Form Sign Up Screen
06 - Attached Properties
07 - Storyboard Animations
08 - Advanced View Models Real World
09 - User Controls Side Menu Content
10 - ItemsControl Chat List & Design Time Data
11 - Dependency Injection & Multiple Projects
12 - MVVM View Model Binding to Animations
13 - Complete Page Animation
14 - Create Chat Message Bubbles
15 - Adaptive Control Design with View Model Binding
16 - Chat Message Title Bar Menu
17 - Chat Message Input Box Control
18 - Styling Scrollbars Custom
19 - Creating Popup Menus
20 - Creating Vertical Popup Menu
21 - Custom Dialog System Message Box Popup
22 - Slide Up Settings Menu
23 - Settings Page UI
24 - Advanced Edit Text Control
25 - Advanced Cross-Control Syncing

Database collations

The default collation for a database can now be specified in the EF model.
This will flow through to generated migrations to set the collation when the database is created.
For example:

 modelBuilder.UseCollation("German_PhoneBook_CI_AS");

Here’s what’s new in this release for ASP.NET Core:

• New component tag helper
• Prevent default actions for events in Blazor apps
• Stop event propagation in Blazor apps
• Validation of nested models in Blazor forms
• Detailed errors during Blazor app development 

It includes a chart control for Windows Forms, HTTP/2 support, GC updates to use less memory, support for CPU limits with Docker, the addition of PowerShell in .NET Core SDK Docker container images, and other improvements.