Visual Studio’s project templates enable you, the developer, to create multiple similar projects more efficiently by defining a common set of starter files. The project templates can be fully customized to meet the needs of a development team, or a group, and can be published to the Visual Studio Marketplace for others to download and use too! Once published, developers can install and access the template through Visual Studio’s New Project Dialog.

The newly designed New Project Dialog for Visual Studio 2019 was built to help developers get to their code faster. Using a search and filter focused experience, we are aiming to provide better discoverability for specific templates to start your application development

 

With this newest Blazor release we’re pleased to announce that Blazor is now in official preview! Blazor is no longer experimental and we are committing to ship it as a supported web UI framework including support for running client-side in the browser on WebAssembly.

A little over a year ago we started the Blazor experimental project with the goal of building a client web UI framework based on .NET and WebAssembly. At the time Blazor was little more than a prototype and there were lots of open questions about the viability of running .NET in the browser. Since then we’ve shipped nine experimental Blazor releases addressing a variety of concerns including component model, data binding, event handling, routing, layouts, app size, hosting models, debugging, and tooling. We’re now at the point where we think Blazor is ready to take its next step.

Some days ago we announced improved Razor tooling support in Visual Studio Code with the latest C# extension. This latest release includes improved Razor diagnostics and support for tag helpers and Blazor apps.

This article will show you the basics of types internals, as of course an example in which the memory for the reference type will be allocated completely on the stack (this is because I am a full-stack programmer).

Disclaimer

This article does not contain material that should be used in real projects. It is simply an extension of the boundaries in which a programming language is perceived.

Before proceeding with the story, I strongly recommend you to read the first post about StructLayout, because there is an example that will be used in this article (However, as always).

In this article, I decided to describe how the functionality of selecting and displaying photos on a specific place on the map was implemented in our photo service gfranq.com. The photo service does not work now.

Since we had a lot of photos in our service and sending requests to database every time the viewport changes was too resource-intensive, it was logical to divide the map into several areas that contain information about the retrieved data. For obvious reasons, these areas have rectangular shape (although hexagonal grid was considered too). As the areas become more spherical at large scales, elements of spherical geometry and tools for it were also considered.

In this article, the following issues were raised:

• Storing and retrieving photos from the database and caching them on the server (SQL, C#, ASP.NET).
• Downloading necessary photos on the client side and saving them to the client cache (JavaScript).
• Recalculation of photos that must be hidden or shown when the viewport changes.
• Elements of spherical geometry.

I propose to look at the internals that are behind the simple lines of initializing of the objects, calling methods, and passing parameters. And, of course, we will use this information in practice — we will subtract the stack of the calling method.

Disclaimer

Before proceeding with the story, I strongly recommend you to read the first post about StructLayout, there is an example that will be used in this article.

All code behind the high-level one is presented for the debug mode, because it shows the conceptual basis. JIT optimization is a separate big topic that will not be covered here.

I would also like to warn that this article does not contain material that should be used in real projects.

First — theory

Any code eventually becomes a set of machine commands. Most understandable is their representation in the form of Assembly language instructions that directly correspond to one (or several) machine instructions.

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

Today we’re announcing the ML.NET 1.0 RC (Release Candidate) (version 1.0.0-preview) which is the last preview release before releasing the final ML.NET 1.0 RTM in 2019 Q2 calendar year.

Soon we will be ending the first main milestone of a great journey in the open that started on May 2018 when releasing ML.NET 0.1 as open source. Since then we’ve been releasing monthly, 12 preview releases so far, as shown in the roadmap below:

In this release (ML.NET 1.0 RC) we have initially concluded our main API changes. For the next sprint we are focusing on improving documentation and samples and addressing major critical issues if needed.

The goal is to avoid any new breaking changes moving forward.

Multithreading

Now let’s talk about thin ice. In the previous sections about IDisposable we touched one very important concept that underlies not only the design principles of Disposable types but any type in general. This is the object’s integrity concept. It means that at any given moment of time an object is in a strictly determined state and any action with this object turns its state into one of the variants that were pre-determined while designing a type of this object. In other words, no action with the object should turn it into an undefined state. This results in a problem with the types designed in the above examples. They are not thread-safe. There is a chance the public methods of these types will be called when the destruction of an object is in progress. Let’s solve this problem and decide whether we should solve it at all.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

Hello. This time we continue to laugh at the normal method call. I propose to get acquainted with the method call with parameters without passing parameters. We will also try to convert the reference type to a number — its address, without using pointers and unsafe code.

Memory<T> and ReadOnlyMemory<T>

There are two visual differences between Memory<T> and Span<T>. The first one is that Memory<T> type doesn’t contain ref modifier in the header of the type. In other words, the Memory<T> type can be allocated both on the stack while being either a local variable, or a method parameter, or its returned value and on the heap, referencing some data in memory from there. However, this small difference creates a huge distinction in the behavior and capabilities of Memory<T> compared to Span<T>. Unlike Span<T> that is an instrument for some methods to use some data buffer, the Memory<T> type is designed to store information about the buffer, but not to handle it. Thus, there is the difference in API.

• Memory<T> doesn’t have methods to access the data that it is responsible for. Instead, it has the Span property and the Slice method that return an instance of the Span type.
• Additionally, Memory<T> contains the Pin() method used for scenarios when a stored buffer data should be passed to unsafe code. If this method is called when memory is allocated in .NET, the buffer will be pinned and will not move when GC is active. This method will return an instance of the MemoryHandle structure, which encapsulates GCHandle to indicate a segment of a lifetime and to pin array buffer in memory.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

Span<T> usage examples

A human by nature cannot fully understand the purpose of a certain instrument until he or she gets some experience. So, let’s turn to some examples.

ValueStringBuilder

One of the most interesting examples in respect to algorithms is the ValueStringBuilder type. However, it is buried deep inside mscorlib and marked with the internal modifier as many other very interesting data types. This means we would not find this remarkable instrument for optimization if we haven’t researched the mscorlib source code.

What is the main disadvantage of the StringBuilder system type? Its main drawback is the type and its basis — it is a reference type and is based on char[], i.e. a character array. At least, this means two things: we use the heap (though not much) anyway and increase the chances to miss the CPU cash.

Another issue with StringBuilder that I faced is the construction of small strings, that is when the resulting string must be short e.g. less than 100 characters. Short formatting raises issues on performance.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

Once in a while we go back to the projects that we have previously checked using PVS-Studio, which results in their descriptions in various articles. Two reasons make these comebacks exciting for us. Firstly, the opportunity to assess the progress of our analyzer. Secondly, monitoring the feedback of the project's authors to our article and the report of errors, which we usually provide them with. Of course, errors can be corrected without our participation. However, it is always nice when our efforts help to make a project better. Roslyn was no exception. The previous article about this project check dates back to December 23, 2015. It's quite a long time, in the view of the progress that our analyzer has made since that time. Since the C# core of the PVS-Studio analyzer is based on Roslyn, it gives us additional interest in this project. As a result, we're as keen as mustard about the code quality of this project. Now let's test it once again and find out some new and interesting issues (but let's hope that nothing significant) that PVS-Studio will be able to find.

Hi. I would like to show you an example of using StructLayout for something more interesting than examples with bytes, ints, and other primitive types, when everything happens quite obviously.

In .NET Core 3.0 we are introducing a new type of application template called Worker Service. This template is intended to give you a starting point for writing long running services in .NET Core. In this walkthrough we will create a worker and run it as a Windows Service.

SafeHandle / CriticalHandle / SafeBuffer / derived types

I feel I’m going to open the Pandora’s box for you. Let’s talk about special types: SafeHandle, CriticalHandle and their derived types.

This is the last thing about the pattern of a type that gives access to an unmanaged resource. But first, let’s list everything we usually get from unmanaged world:

The first and obvious thing is handles. This may be an meaningless word for a .NET developer, but it is a very important component of the operating system world. A handle is a 32- or 64-bit number by nature. It designates an opened session of interaction with an operating system. For example, when you open a file you get a handle from the WinApi function. Then you can work with it and do Seek, Read or Write operations. Or, you may open a socket for network access. Again an operating system will pass you a handle. In .NET handles are stored as IntPtr type;

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

We are now publishing .NET Core container images to Microsoft Container Registry (MCR). We have also made other changes to the images we publish, described in this post.

Important: You will need to change FROM statements in Dockerfile files and docker pull commands as a result of these changes. 3.0 references need to be changed now. Most 1.x and 2.x usages can be changed over time. The new tag scheme is decribed in this post and are provided at the microsoft-dotnet-core repo, our new home on Docker Hub.

Summary of changes:

• .NET Core images are now published to Microsoft Container Registry.
• Updates will continue to be published to Docker Hub, for .NET Core 1.x and 2.x.
• .NET Core 3.0 will only be published to MCR.
• Nano Server 2016 images are no longer supported or published.

Disposable pattern (Disposable Design Principle)

I guess almost any programmer who uses .NET will now say this pattern is a piece of cake. That it is the best-known pattern used on the platform. However, even the simplest and well-known problem domain will have secret areas which you have never looked at. So, let’s describe the whole thing from the beginning for the first-timers and all the rest (so that each of you could remember the basics). Don’t skip these paragraphs — I am watching you!

If I ask what is IDisposable, you will surely say that it is

public interface IDisposable
{
    void Dispose();
}

What is the purpose of the interface? I mean, why do we need to clear up memory at all if we have a smart Garbage Collector that clears the memory instead of us, so we even don’t have to think about it. However, there are some small details.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

MonoGame is an Open Source implementation of the Microsoft XNA 4 Framework. It allows developers to create games for iOS, Android, MacOS, Linux, Windows, Xbox and PlayStation.

In this episode, Brian Peek comes on to talk to us about how to get started with MonoGame, and also show some interesting games that have been built with the framework.

Starting from .NET Core 2.0 and .NET Framework 4.5 we can use new data types: Span and Memory. To use them, you just need to install the System.Memory nuget package:

PM> Install-Package System.Memory

These data types are notable because the CLR team has done a great job to implement their special support inside the code of .NET Core 2.1+ JIT compiler by embedding these data types right into the core. What kind of data types are these and why are they worth a whole chapter?

If we talk about problems that made these types appear, I should name three of them. The first one is unmanaged code.

Both the language and the platform have existed for many years along with means to work with unmanaged code. So, why release another API to work with unmanaged code if the former basically existed for many years? To answer this question, we should understand what we lacked before.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

In 2013, while working at GFRANQ photo service, I participated in the development of an eponymous web service for publishing and processing photos. Filters and transformations were defined in the file with parameters, and all processing was carried out on the server. During service development, there was a need to support these transformations on the client side for the preview. According to Larry Wall, one of the virtues of a programmer is laziness. Therefore, as truly lazy programmers, we thought about the possibility of using the same code on both the server and client sides. The entire development was conducted in C#. After researching the libraries and a couple of attempts, we proudly concluded that this was possible and began to write the universal code.

Why is this article needed? Indeed, 6 years have passed since 2013, and many technologies have lost their relevance, for example, Script#. On the other hand, new ones have appeared. For example, Bridge.NET or Blazor based on the fancy WebAssembly.

Nevertheless, some ideas can still be used. In this article I tried to describe them as detailed as possible. I hope that the mention of Silverlight and Flash will cause a smile with a hint of nostalgia, and not a desire to criticize the old solutions. Anyway, they have contributed to the development of the web industry.