.NET *

We’re announcing .NET Core 3.1 Preview 2. .NET Core 3.1 will be a small and short release focused on key improvements in Blazor and Windows desktop, the two big additions in .NET Core 3.0.. It will be a long term support (LTS) release with an expected final ship date of December 2019.

You can download .NET Core 3.1 Preview 2 on Windows, macOS, and Linux.

• .NET Core 3.1 Preview 2 SDK and Runtime
• Docker images

ASP.NET Core and EF Core are also releasing updates today.

Visual Studio 16.4 Preview 3 and Visual Studio for Mac 8.4 Preview 3 are also releasing today. They are required updates to use .NET Core 3.1 Preview 2. Visual Studio 16.4 includes .NET Core 3.1, so just updating Visual Studio will give you both releases.

Details:

• .NET Core 3.1 release notes
• GitHub release
• GitHub issue for Preview 2

In September, we released .NET Core support for building Windows desktop applications, including WPF and Windows Forms. Since then, we have been delighted to see so many developers share their stories of migrating desktop applications (and controls libraries) to .NET Core. We constantly hear stories of .NET Windows desktop developers powering their business with WPF and Windows Forms, especially in scenarios where the desktop shines, including:

• UI-dense forms over data (FOD) applications
• Responsive low-latency UI
• Applications that need to run offline/disconnected
• Applications with dependencies on custom device drivers

This is just the beginning for Windows application development on .NET Core. Read on to learn more about the benefits of .NET Core for building Windows applications.

This is a guest post from the Orleans team. Orleans is a cross-platform framework for building distributed applications with .NET. For more information, see https://github.com/dotnet/orleans.

We are excited to announce the Orleans 3.0 release. A great number of improvements and fixes went in, as well as several new features, since Orleans 2.0. These changes were driven by the experience of many people running Orleans-based applications in production in a wide range of scenarios and environments, and by the ingenuity and passion of the global Orleans community that always strives to make the codebase better, faster, and more flexible. A BIG Thank You to all who contributed to this release in various ways!

SameSite is a 2016 extension to HTTP cookies intended to mitigate cross site request forgery (CSRF). The original design was an opt-in feature which could be used by adding a new SameSite property to cookies. It had two values, Lax and Strict.

Setting the value to Lax indicated the cookie should be sent on navigation within the same site, or through GET navigation to your site from other sites. A value of Strict limited the cookie to requests which only originated from the same site. Not setting the property at all placed no restrictions on how the cookie flowed in requests. OpenIdConnect authentication operations (e.g. login, logout), and other features that send POST requests from an external site to the site requesting the operation, can use cookies for correlation and/or CSRF protection. These operations would need to opt-out of SameSite, by not setting the property at all, to ensure these cookies will be sent during their specialized request flows.

Google is now updating the standard and implementing their proposed changes in an upcoming version of Chrome. The change adds a new SameSite value, «None», and changes the default behavior to «Lax». This breaks OpenIdConnect logins, and potentially other features your web site may rely on, these features will have to use cookies whose SameSite property is set to a value of «None».

However browsers which adhere to the original standard and are unaware of the new value have a different behavior to browsers which use the new standard as the SameSite standard states that if a browser sees a value for SameSite it does not understand it should treat that value as «Strict». This means your .NET website will now have to add user agent sniffing to decide whether you send the new None value, or not send the attribute at all.

Since the release of Blazor Server with .NET Core 3.0 last month lots of folks have shared their excitement with us about being able to build client-side web UI with just .NET and C#. At the same time, we’ve also heard lots of questions about what Blazor Server is, how it relates to Blazor WebAssembly, and what scenarios Blazor Server is best suited for. Should you choose Blazor Server for your client-side web UI needs, or wait for Blazor WebAssembly? This post seeks to answer these questions, and to provide insights into how Blazor Server performs at scale and how we envision Blazor evolving in the future.

What is Blazor Server?

Blazor Server apps host Blazor components on the server and handle UI interactions over a real-time SignalR connection. As the user interacts with the app, the UI events are sent to the server over the connection to be handled by the various components that make up the app. When a component handles a UI event, it’s rendered based on its updated state. Blazor compares the newly rendered output with what was rendered previously and send the changes back to the browser and applies them to the DOM.

We’re announcing .NET Core 3.1 Preview 1. .NET Core 3.1 will be a small release focused on key improvements in Blazor and Windows desktop, the two big additions in .NET Core 3.0. It will be a long term support (LTS) release with an expected final ship date of December 2019.

You can download .NET Core 3.1 Preview 1 on Windows, macOS, and Linux.

• .NET Core 3.0 SDK and Runtime
• Docker images

ASP.NET Core and EF Core are also releasing updates today.

Visual Studio 16.4 Preview 2 and is also releasing today. It is a recommended update to use .NET Core 3.1 Preview 1. Visual Studio 16.4 includes .NET Core 3.1, so just updating Visual Studio will give you both releases.

Details:

• .NET Core 3.1 release notes

Known Issue: The Visual Studio 16.4 installer may uninstall the .NET Core 3.0 Runtime when it installs .NET Core 3.1. We recommend you re-in-install or repair the .NET Core 3.0 SDK in that case.

This article reviews the results of a second check of the Orchard project with the PVS-Studio static analyzer. Orchard is an open-source content manager system delivered as part of the ASP.NET Open Source Gallery under the non-profit Outercurve Foundation. Today's check is especially interesting because both the project and the analyzer have come a long way since the first check, and this time we'll be looking at new diagnostic messages and some nice bugs.

With October release of the Python extension, we’re excited to announce the support of native editing of Jupyter notebooks inside Visual Studio Code! You can now directly edit .ipynb files and get the interactivity of Jupyter notebooks with all of the power of VS Code.

You can manage source control, open multiple files, and leverage productivity features like IntelliSense, Git integration, and multi-file management, offering a brand-new way for data scientists and developers to experiment and work with data efficiently. You can try out this experience today by downloading the latest version of the Python extension and creating/opening a Jupyter Notebook inside VS Code.



Since the initial release of our data science experience in VS Code, one of the top features that users have requested has been a more notebook-like layout to edit their Jupyter notebooks inside VS Code. In the rest of this post we’ll take a look at the new capabilities this offers.

Styles, by default, in wpf, in Avalonia, are neutral, and far from always suitable for the tasks we need. In this article, I would like to talk about the basics of working with styles and show a couple of interesting examples.

Over the past year, the Visual Studio for Mac team updated the editors within the IDE to be faster, more fluent and more productive. We did this by building a macOS-native editor interface on top of the same editor backend as Visual Studio on Windows. In version 8.1 we introduced the new C# editor. This was followed by the new XAML editor in 8.2. And most recently, we updated our web languages to utilize the new editors in version 8.3, completing the process we set out to do a year ago. To celebrate this accomplishment, I wanted to share a bit of detail regarding the design and implementation of the new editors along with my five favorite new features in the Visual Studio for Mac code editors.

At the core of the updated editors within Visual Studio for Mac is the shared language service with Visual Studio on Windows. What this means is that the same backend that powers the Windows version of Visual Studio now powers the macOS version as well. This includes IntelliSense, Roslyn, text logic, and all the language services behind the scenes. The only portion not shared between Windows and macOS is the UI layer, which stays native for each platform. In the case of macOS, that means using macOS frameworks like Cocoa and CoreText to power the UI experience. By using a native UI, while also being able to utilize support for native input methods as well as support for right-to-left languages, font ligatures and other advanced graphical features.

Sometimes we don’t understand how the regular expression that we have composed works and want to check. There are many applications like regex101.com or vs code. I wanted to add one more to this list.

In this article we will see how you can wrap Regex in cross-platform graphics and create a simple application for testing regular expressions.

We are excited to announce updates to Model Builder and improvements in ML.NET. You can learn more in the «What’s new in ML.NET?.» session at .NET Conf.

ML.NET is an open-source and cross-platform machine learning framework (Windows, Linux, macOS) for .NET developers.

ML.NET offers Model Builder (a simple UI tool) and CLI to make it super easy to build custom ML Models using AutoML.

Using ML.NET, developers can leverage their existing tools and skillsets to develop and infuse custom AI into their applications by creating custom machine learning models for common scenarios like Sentiment Analysis, Recommendation, Image Classification and more!..

This article is a brief explanation about how using a common language keywords might have an influence on the budget of IT-infrastructure of a project or help to achieve some limitations/restrictions of hosting infrastructure and, moreover, will be a good sing of the quality and maturity of the source code.

This article is the story how we once decided to improve our internal SelfTester tool that we apply to test the quality of the PVS-Studio analyzer. The improvement was simple and seemed to be useful, but got us into some troubles. Later it turned out that we'd better gave up the idea.

Hello reader. Quite a lot of time has passed since the release of .NET Core 2.1. And such cool innovations as Span and Memory are already widely known, you can read, see and hear a lot about them. However, unfortunately, library called System.IO.Pipeslines did not receive the same attention. Almost everything there is on this topic is the only post that have been translated and copied on many resources. There should be more information about that technology to look on it from different angles.

.NET Core libraries is one of the most popular C# projects on GitHub. It's hardly a surprise, since it's widely known and used. Owing to this, an attempt to reveal the dark corners of the source code is becoming more captivating. So this is what we'll try to do with the help of the PVS-Studio static analyzer. What do you think – will we eventually find something interesting?

This is a short story about how PVS-Studio helped us find an error in the source code of the library used in PVS-Studio. And it was not a theoretical error but an actual one — the error appeared in practice when using the library in the analyzer.

We like to search for errors in Microsoft projects. Why? It's simple: their projects are usually easy to check (you can work in Visual Studio environment for which PVS-Studio has a convenient plugin) and they contain few errors. That's why the usual work algorithm is as follows: find and download an open source project from MS; check it; choose interesting errors; make sure there are few of them; write an article without forgetting to praise the developers. Great! Win-win-win: it took a little time, the bosses are glad to see new materials in the blog, and karma is fine. But this time «something went wrong». Let's see what we have found in the source code of Windows Forms and whether we should speak highly of Microsoft this time.

User interfaces of modern enterprise applications are quite complex. You, as a developer, often need to implement in-app navigation, validate user input, show or hide screens based on user preferences. For better UX, your app should be capable of saving state to the disk when the app is suspending and of restoring state when the app is resuming.

ReactiveUI provides facilities allowing you to persist application state by serializing the view model tree when the app is shutting down or suspending. Suspension events vary per platform. ReactiveUI uses the Exit event for WPF, ActivityPaused for Xamarin.Android, DidEnterBackground for Xamarin.iOS, OnLaunched for UWP.

In this tutorial we are going to build a sample application which demonstrates the use of the ReactiveUI Suspension feature with Avalonia — a cross-platform .NET Core XAML-based GUI framework. You are expected to be familiar with the MVVM pattern and with reactive extensions before reading this note. Steps described in the tutorial should work if you are using Windows 10 or Ubuntu 18 and have .NET Core SDK installed. Let's get started! Source code of the app described in this tutorial is available on GitHub.