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What's New for ASP.NET Core in .NET Core 3.1 Preview 1

With .NET Core 3.1 Preview 1 announced this week, Microsoft highlighted what's new in the ASP.NET Core component, which isn't much.

That's because the first preview release of .NET Core 3.1 included mostly bug fixes for ASP.NET Core, said Daniel Roth, principal program manager for ASP.NET.

The new preview does, however, include an update to Blazor WebAssembly, the client-side part of Blazor, the red-hot project that allows for developers to use C# instead of JavaScript in Web projects.

"Alongside this .NET Core 3.1 Preview 1 release, we've also released a Blazor WebAssembly update, which now requires .NET Core 3.1," Roth said. "To use Blazor WebAssembly you will need to install .NET Core 3.1 Preview 1 as well as the latest preview of Visual Studio."

Here's a summation of what's new for ASP.NET Core in the .NET Core 3.1 Preview 1:

  • Partial class support for Razor components: "Razor components are now generated as partial classes. You can author the code for a Razor component using a code-behind file defined as a partial class instead of defining all the code for the component in a single file."
  • Pass parameters to top-level components: "Blazor Server apps can now pass parameters to top-level components during the initial render. Previously you could only pass parameters to a top-level component with RenderMode.Static. With this release, both RenderMode.Server and RenderModel.ServerPrerendered are now supported. Any specified parameter values are serialized as JSON and included in the initial response." (See this article, with a comment from Roth, for more on this feature).
  • Support for shared queues in HttpSysServer: "In addition to the existing behavior where HttpSysServer created anonymous request queues, we've added to ability to create or attach to an existing named HTTP.sys request queue. This should enable scenarios where the HTTP.Sys controller process that owns the queue is independent to the listener process making it possible to preserve existing connections and enqueued requests between across listener process restarts."
  • Breaking changes for SameSite cookies: "This release updates the behavior of SameSite cookies in ASP.NET Core to conform to the latest standards being enforced by browsers. For details on these changes and their impact on existing apps see https://github.com/aspnet/Announcements/issues/390."

The ASP.NET Core release notes contain more details on bug fixes and new features.

About the Author

David Ramel is an editor and writer at Converge 360.

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