Blazor and Single-Page Applications (SPA)

Hi devs,

As web developers, we’re constantly looking for ways to build fast, interactive, and seamless web applications. Blazor is Microsoft’s answer to modern web development challenges, offering a fresh take on Single-Page Applications (SPA). But what exactly is Blazor, and how does it fit into the SPA model? Let’s dive in.

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What is a Single-Page Application (SPA)?

A Single-Page Application is a web app that dynamically updates the user interface without fully reloading the page. This results in a smoother and faster user experience, as only the necessary data is fetched from the server.

Common frameworks like React, Angular, and Vue.js dominate the SPA world, but Blazor introduces a .NET-based approach to SPAs, allowing C# developers to use their existing skills to build rich, interactive applications.

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What is Blazor?

Blazor is a framework built on .NET for creating interactive web applications. It leverages WebAssembly (Blazor WebAssembly) or SignalR (Blazor Server) to run C# code directly in the browser or on the server.

Blazor allows developers to:

• Write client-side and server-side code using C#.
• Share code between the client and server.
• Build reusable components like traditional SPA frameworks.

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Blazor vs. Traditional SPA Frameworks

Feature	Blazor	React/Angular/Vue
Language	C#	JavaScript/TypeScript
Performance	Blazor Server: Fast; Blazor WASM: Depends on payload size	Generally fast
Learning Curve	Easier for .NET devs	Easier for JavaScript devs
Ecosystem	.NET-centric	Rich JS ecosystem
SEO	Blazor Server: Great; Blazor WASM: Requires configuration	Varies by framework

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Blazor SPA Models

Blazor supports two main hosting models:

1. Blazor Server

   • Runs on the server and uses SignalR to communicate with the client.
   • Pros: Smaller initial load, works on older browsers, great for SEO.
   • Cons: Latency depends on the server connection.

2. Blazor WebAssembly (WASM)

   • Runs entirely in the browser using WebAssembly.
   • Pros: No server dependency after load, better offline support.
   • Cons: Larger initial payload.

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Building a Blazor SPA: A Quick Example

Let’s see how easy it is to create a SPA using Blazor.

Step 1: Create a New Blazor Project

Use the .NET CLI to create a Blazor WebAssembly project:

dotnet new blazorwasm -o BlazorSPA  
cd BlazorSPA  
dotnet run  

Step 2: Add a Component

Blazor components are the building blocks of SPAs. Create a new component, WeatherForecast.razor:

@code {  
    private WeatherData[] forecasts;  

    protected override async Task OnInitializedAsync()  
    {  
        forecasts = await Http.GetFromJsonAsync<WeatherData[]>("/api/weather");  
    }  

    private class WeatherData  
    {  
        public string Date { get; set; }  
        public int TemperatureC { get; set; }  
        public string Summary { get; set; }  
    }  
}  

<h3>Weather Forecast</h3>  
<table>  
    <thead>  
        <tr>  
            <th>Date</th>  
            <th>Temp. (C)</th>  
            <th>Summary</th>  
        </tr>  
    </thead>  
    <tbody>  
        @foreach (var forecast in forecasts)  
        {  
            <tr>  
                <td>@forecast.Date</td>  
                <td>@forecast.TemperatureC</td>  
                <td>@forecast.Summary</td>  
            </tr>  
        }  
    </tbody>  
</table>  

Step 3: Run the App

Navigate to http://localhost:5000 to see your interactive SPA in action!

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Why Choose Blazor for SPAs?

Blazor shines for teams already invested in the .NET ecosystem. Its seamless integration with backend systems, strong type safety, and reusable components make it a great choice for enterprise applications.

Key Advantages:

1. Single Language: Use C# for both client and server.
2. Reusable Components: Build once, use anywhere.
3. Integration: Tight coupling with ASP.NET Core for API calls and identity management.
4. SEO Support: Especially strong with Blazor Server.

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Conclusion

Blazor brings the power of .NET to SPA development, making it easier for developers to build interactive web applications with modern features. Whether you’re considering Blazor Server or Blazor WebAssembly, you’re equipped with a tool that simplifies development without compromising on performance or scalability.