Blazor 0.9.0 experimental release now available

Daniel Roth

Blazor 0.9.0 is now available! This release updates Blazor with the Razor Components improvements in .NET Core 3.0 Preview 3.

New Razor Component improvements now available to Blazor apps:

  • Improved event handling
  • Forms & validation

Checkout the ASP.NET Core 3.0 Preview 3 announcement for details on these improvements. See also the Blazor 0.9.0 release notes for additional details.

Note: The Blazor templates have not been updated to use the new .razor file extension for Razor Components in this release. This update will be done in a future release.

Get Blazor 0.9.0

To get started with Blazor 0.9.0 install the following:

  1. .NET Core 3.0 Preview 3 SDK (3.0.100-preview3-010431)
  2. Visual Studio 2019 (Preview 4 or later) with the ASP.NET and web development workload selected.
  3. The latest Blazor extension from the Visual Studio Marketplace.
  4. The Blazor templates on the command-line:

    dotnet new -i Microsoft.AspNetCore.Blazor.Templates::0.9.0-preview3-19154-02

You can find getting started instructions, docs, and tutorials for Blazor at

Upgrade to Blazor 0.9.0

To upgrade your existing Blazor apps to Blazor 0.9.0 first make sure you’ve installed the prerequisites listed above.

To upgrade a Blazor 0.8.0 project to 0.9.0:

  • Update the Blazor packages and .NET CLI tool references to 0.9.0-preview3-19154-02.
  • Update the remaining Microsoft.AspNetCore.* packages to 3.0.0-preview3-19153-02.
  • Remove any usage of JSRuntime.Current and instead use dependency injection to get the current IJSRuntime instance and pass it through to where it is needed.

Give feedback

We hope you enjoy this latest preview release of Blazor. As with previous releases, your feedback is important to us. If you run into issues or have questions while trying out Blazor, file issues on GitHub. You can also chat with us and the Blazor community on Gitter if you get stuck or to share how Blazor is working for you. After you’ve tried out Blazor for a while please let us know what you think by taking our in-product survey. Click the survey link shown on the app home page when running one of the Blazor project templates:

Blazor survey

Thanks for trying out Blazor!


Discussion is closed. Login to edit/delete existing comments.

  • Premchand PeddakotlaMicrosoft employee 0

    I was playing with 0.9.0-preview3-19154-02 version of Microsoft.AspNetCore.Blazor.Server. I create a project using Asp.Net Core hosted with Client, Server and Shared project. On the server project, I am authenticating the user with AAD and its working fine. I got all the claims and user information after authenticating with AAD. Now I want to use that user information on the client side such as display the login user information on the page. But the problem is, HttpContextAccessor is coming as null to the client project.
    I have registered the IHttpContextSevices on the server project using the syntax below
    And I injected IHttpContextAccessor in the client project. But IHttpContextAccessor is coming as null. Let me know if I am missing anything on the client project?

  • Chris Herridge 0

    I’m really enjoying Blazor, so much so i’ve started working on a set of libraries for assisting with some of the more complex workloads i’ve seen in MVC.. For example a controller method that returns async IAsyncEnumerable<T> … being automatically wrapped in such a way it streams (chunked, with progress, status and cancelling) down to the client.
    I’ve also been working on the concept of conversational MVC actions. For example
    public async Task<string> ConversationTest(MyP1Class){
    //perhaps do some processing on the inputs, then find you need to confirm something with the user
    //so you can go:
    var alertResult = await Alert(“Title”, “alert”, “A message about the issue you’ve just found, server side.”, new ButtonBase[] {new ButtonBase() { Title= “Ok”, Position= ButtonPosition.Primary},new ButtonBase() { Title= “Cancel”, Position= ButtonPosition.Secondary}});

    This then holds the original request, uses sigr to go back to the client, do some UI data capture (in a modal dialog). Get info back from UI and release the server thread.
    These are all just concepts at the moment, but if anyone’s interested in joining me with this.
    Come say hi:

  • James Heffer 0

    If you need help with learning how to use Blazor, you can join the Blazor Discord server by clicking this link here:… This is an ever growing community of like minded coders 🙂 

  • Camble . 0

    The brief survey link takes you to a ReSharper survey.

  • מוטי דר. 0

    Hey, How or where can I hosting my blazor website? I can not find any place. Do i need cloud or virtual server? Do I need windows with iis?
    Today I’m hosting it in my computer, but u know.. need 24/7 availability. tx Moti

  • Jeffrey Gordon 0

    This is really cool. Leaning between this and React/Node-Express for next version of my product. Brief Survet takes me to feedback for Resharper. My only “complaint” is memory usage and slow start up on mobile devices. It’s still in preview, I bet you folks are still working out performance 🙂

  • Jeffrey Gordon 0

    This is really cool. Leaning between this and React/Node-Express for next version of my product. “Brief Survey” link takes me to feedback for Resharper. My only “complaint” is browser memory usage (which isn’t a deal-breaker all things considered) and slow start up on mobile devices (which is, 5 seconds of “loading” isn’t acceptable). It’s still in preview, I bet you folks are still working out performance 🙂

  • Yordan Yanakiev 0

    Good lords. I can’t wait for this thing. I really need the full stack client side right now !This project if goes into the right direction of possibility of bringing full stack RIA into browser and behind it can live a pure C# – well the possibilities are mind blowing.

  • Mohammad M 0

    Nice to see progress on Blazor. I really believe this will have a great impact on .NET development. However can’t you guys inform us which version of Entity Framework Core goes along with this version (0.9.0). I can’t get this version to work on any EF Core versions.

  • Mohammad Komaei 0

    Please show us how to start (F5) a blazor project with vscode.
    It give us error : A fatal error was encountered. The library ‘hostpolicy.dll’ required to execute the application was not found in ‘E:\Projects\Blazorr\bin\Debug\netstandard2.0’.Failed to run as a self-contained app. If this should be a framework-dependent app, add the E:\Projects\Blazorr\bin\Debug\netstandard2.0\Blazorr.runtimeconfig.json file specifying the appropriate framework.The target process exited without raising a CoreCLR started event. Ensure that the target process is configured to use .NET Core. This may be expected if the target process did not run on .NET Core.The program ‘[9964] Blazorr.dll’ has exited with code -2147450749 (0x80008083).

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