.NET 8 Preview 4 is now available and includes many great new improvements to ASP.NET Core.

Here’s a summary of what’s new in this preview release:

Blazor

Streaming rendering with Blazor components

Handling form posts with Blazor SSR

Route to named elements in Blazor

Webcil packaging for Blazor WebAssembly apps

API authoring

Expanded support for form binding in minimal APIs

API project template includes .http file

Native AOT

Logging and exception handling in compile-time generated minimal APIs

ASP.NET Core top-level APIs annotated for trim warnings

Reduced app size with configurable HTTPS support

Worker Service template updates

Additional default services configured in the slim builder

API template JSON configuration changes

Support for JSON serialization of compiler-generated IAsyncEnumerable unspeakable types

Authentication and authorization

Identity API endpoints

Improved support for custom authorization policies with IAuthorizationRequirementData

ASP.NET Core metrics

For more details on the ASP.NET Core work planned for .NET 8 see the full ASP.NET Core roadmap for .NET 8 on GitHub. 

Here’s a summary of what’s new in this preview release:

• ASP.NET Core support for native AOT
• Server-side rendering with Blazor
• Render Razor components outside of ASP.NET Core
• Sections support in Blazor
• Monitor Blazor Server circuit activity
• SIMD enabled by default for Blazor WebAssembly apps
• Request timeouts
• Short circuit routes 

The Blazor component model to be included in ASP.NET Core and shipped with .NET Core 3.0 was given the new name "Razor Components" to differentiate it from the ability to run .NET in the browser, Roth said.  

Free Bootstrap 5.3 components for ASP.NET Blazor. 

BlazorStrap: Bootstrap 4 Components for Blazor Framework 

.NET Conf: Focus on Blazor is a free, one-day livestream event that features speakers from the community and .NET product teams that are working on building web apps with C# and Blazor. You don't need to use JavaScript anymore with Blazor technology! Blazor lets you build interactive web UIs using C# instead of JavaScript. 

Data Analyst 2022 | Data Analytics Full Course | Data Analytics Tutorial For Beginners |Simplilearn - YouTube 

<Comp1>This is a content coming from the parent</Comp1>

@page "/ParentComponent"

<h1 class="text-danger">Parent Child Component</h1>

<ChildComponent Title="This title is passed as a parameter from the Parent Component">
    A `Render Fragment` from the parent!
</ChildComponent>

<ChildComponent Title="This is the second child component"></ChildComponent>

@code {

}

<li class="nav-item px-3">
    <NavLink class="nav-link" href="ParentComponent">
       <span class="oi oi-list-rich" aria-hidden="true"></span> Parent/Child Relation
    </NavLink>
</li>

<div>
    <div class="alert alert-info">@Title</div>
    <div class="alert alert-success">
        @if (ChildContent == null)
        {
            <span> Hello, from Empty Render Fragment </span>
        }
        else
        {
            <span>@ChildContent</span>
        }
    </div>
</div>


@code {
    [Parameter]
    public string Title { get; set; }

    [Parameter]
    public RenderFragment ChildContent { get; set; }
}

<button class="btn btn-danger"
        @onclick="@(() => OnClickBtnMethod.InvokeAsync((1, "A message from child!")))">
   Show a message from the child!
</button>


@code {
    // ...

    [Parameter]
    public EventCallback<(int, string)> OnClickBtnMethod { get; set; }
}

@page "/ParentComponent"

<h1 class="text-danger">Parent Child Component</h1>

<ChildComponent
    OnClickBtnMethod="ShowMessage"
    Title="This title is passed as a parameter from the Parent Component">
    A `Render Fragment` from the parent!
</ChildComponent>

<ChildComponent Title="This is the second child component">
    <p><b>@MessageText</b></p>
</ChildComponent>

@code {
    string MessageText = "";

    private void ShowMessage((int Value, string Message) args)
    {
        MessageText = args.Message;
    }
}

@code {
    // ...

    [Parameter]
    public RenderFragment ChildContent { get; set; }

    [Parameter]
    public RenderFragment DangerChildContent { get; set; }
}

<ChildComponent
    OnClickBtnMethod="ShowMessage"
    Title="This title is passed as a parameter from the Parent Component">
    <ChildContent>
        A `Render Fragment` from the parent!
    </ChildContent>
    <DangerChildContent>
        A danger content from the parent!
    </DangerChildContent>
</ChildComponent>

    @if(DangerChildContent == null)
    {
        @if (ChildContent == null)
        {
            <span> Hello, from Empty Render Fragment </span>
        }
        else
        {
            <span>@ChildContent</span>
        }
    }
    else
    {
        <span>@DangerChildContent</span>
    }

Here’s what’s new in this preview release:

• Improved Blazor accessibility
• Required Blazor component parameters
• Efficient byte array transfers for JavaScript interop
• Optional parameters for view component tag helpers
• Angular template updated to Angular 12
• OpenAPI support for minimal APIs
• Inject services into minimal APIs without [FromServices] attribute
• Configure the accept socket for Kestrel
• IHttpActivityFeature
• Long running activity tag for SignalR connections
• WebSocket compression
• SignalR WebSockets TestServer support
• New OnCheckSlidingExpiration event for controlling cookie renewal
• ClientCertificateMode.DelayCertificate