#NET SDK GENERATOR#
#NET SDK CODE#

#NET SDK GENERATOR#

In this guide, you'll explore the creation of a source generator using the ISourceGenerator API.Ĭreate a. This would reduce the number of times a mistyped string literal leads to a request not hitting the correct controller. With a Source Generator, routing can be strongly typed with the necessary strings being generated as a compile-time detail. We're investigating how Source Generators can be used to obviate the need for juggling MSBuild tasks like this, since Source generators don't just offer some performance benefits, but also allows tools to operate at the right level of abstraction.Īnother capability Source Generators can offer is obviating the use of some 'stringly typed' APIs, such as how ASP.NET Core routing between controllers and razor pages work. As you might imagine, calling the compiler more than once affects the total time it takes to build your app. Some scenarios involve calling the MSBuild C# task (called CSC) multiple times so they can inspect data from a compilation.

Source Generators can improve performance in ways that aren't limited to reflection at run time to discover types as well. Using source generators could result in some faster startup times, since an action happening at run time today could get pushed into compile time.

#NET SDK CODE#

A generator can analyze your source code and emit the code it needs to 'wire up' your app. With a Source Generator, the controller discovery phase of startup could instead happen at compile time. Although this performance penalty isn't enormous, it's somewhat of a fixed cost that you can’t improve yourself in your own app. Although this enables you to write straightforward code with powerful abstractions, it comes with a performance penalty at run time: when your web service or app first starts up, it can’t accept any requests until all the runtime reflection code that discovers information about your code is finished running. A common scenario is to perform some analysis of user code when an app starts up and use that data to generate things.įor example, ASP.NET Core uses reflection when your web service first runs to discover constructs you've defined so that it can 'wire up' things like controllers and razor pages. There are countless scenarios for using it. Runtime reflection is a powerful technology that was added to. Source Generators can be an improvement over each approach.

Intermediate Language (IL) weaving (not discussed in this article).

There are three general approaches to inspecting user code and generating information or code based on that analysis used by technologies today:

NET Standard 2.0 assemblies can be used as Source Generators. NET Standard components can be loaded and run.Ĭurrently only. NET Standard 2.0 assembly that is loaded by the compiler along with any analyzers. Source generators run as a phase of compilation visualized below:Ī Source Generator is a. If you're familiar with Roslyn Analyzers, you can think of Source Generators as analyzers that can emit C# source code. Your generator then emits C# code back into the same compilation that is based on the data you've analyzed. You can inspect user code with all of the rich metadata that the compiler builds up during compilation.

When combined, these two things are what make Source Generators so useful. In other words, you can provide additional source code as input to a compilation while the code is being compiled. Generate C# source files that can be added to a compilation object during compilation. This object can be inspected, and you can write code that works with the syntax and semantic models for the code being compiled, just like with analyzers today. Retrieve a compilation object that represents all user code that is being compiled. It inspects your program to produce additional source files that are compiled together with the rest of your code.Ī Source Generator is a new kind of component that C# developers can write that lets you do two major things: In this way, you have code that runs during compilation. The generator can create new C# source files on the fly that are added to the user's compilation. Source Generators let C# developers inspect user code as it is being compiled. This article provides an overview of Source Generators that ships as part of the.

Net sdk