Web development is always changing, and sometimes it feels like you need a superpower to keep up. Luckily, Microsoft’s Blazor framework is here to make life easier. It lets you build interactive web applications using C# instead of JavaScript, opening up a fresh path for both seasoned .NET developers and web enthusiasts looking for new alternatives.
What Is Blazor All About?
At its heart, Blazor is an open-source web framework that lets you create dynamic user interfaces with C#. Instead of writing all your client-side code in JavaScript, you can stick to a language you already know and love. Blazor taps into familiar technologies like HTML and CSS for designing your pages, but it switches up the usual JavaScript with C# for the logic. This shift not only streamlines your workflow if you’re a .NET fan but also paves the way for building both client and server-side applications seamlessly.
The Journey of Blazor
Blazor’s story began around 2017 as a bit of an experiment at Microsoft—its name cleverly mixes “Browser” and “Razor” (the ASP.NET templating engine). Back then, many wondered if running C# in the browser could really work. Today, thanks to a lot of dedication and innovation, Blazor is a mature, production-ready framework powering everything from enterprise applications to public websites. Its creator, Steve Sanderson, envisioned a world where developers wouldn’t be boxed into using JavaScript, and that vision is now a reality.
Blazor Hosting Models: Making the Right Choice
One of the coolest things about Blazor is its flexibility. You can choose between two primary hosting models, each with its own perks:
Blazor WebAssembly (Client-Side)
When you use Blazor WebAssembly, your entire application runs directly in the browser using WebAssembly. Here’s how it works:
- How It Runs: Your browser downloads a small .NET runtime along with your application code and its dependencies.
- Key Perks:
- Offline Capabilities: Once loaded, the app can work even without a continuous internet
connection.
- Less Server Strain: Since the heavy lifting happens on the client
side, your server isn’t overwhelmed.
- Flexible Hosting: You can host your app on any static web server.
Here is a quick peek at a simple Blazor WebAssembly component:
@page "/counter"
<h1>Counter</h1>
<p>Current count: @currentCount</p>
<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>
@code {
private int currentCount = 0;
private void IncrementCount()
{
currentCount++;
}
}
Considerations:
Be mindful that the initial load might be a bit slower since the browser has to download the .NET runtime. Plus, while modern browsers support WebAssembly, older ones might struggle.
Blazor Server
In the Blazor Server model, your application logic runs on the server, and the browser handles the display:
How It Works: The browser downloads a lightweight script that opens a real-time connection (using SignalR) to the server. This connection lets the server process user events and send back updates.
Key Perks:
Fast Start-Up: Since there’s no bulky runtime download, the app loads quickly.
Broader Device Support: Even less powerful devices can run the app smoothly because the
heavy work is done on the server.
Instant Access: The app can access databases and other server resources directly.
Here’s a snippet showing how to configure a Blazor Server app in your Startup.cs:
public void ConfigureServices(IServiceCollection services)
{
services.AddRazorPages();
services.AddServerSideBlazor();
services.AddSingleton<WeatherForecastService>();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Error");
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapBlazorHub();
endpoints.MapFallbackToPage("/_Host");
});
}
Considerations:
This model requires a stable, continuous connection. Each active user keeps an open connection to the server, which means scalability and latency need to be managed carefully.
Crafting Interactive Components
One of Blazor’s greatest strengths is its component-based architecture. Think of components as the building blocks of your app—self-contained pieces that can be reused and nested as needed. Each component is a blend of HTML and C# code, typically stored in a .razor file.
For example, here’s a friendly, reusable alert component:
@if (Show)
{
<div class="alert alert-@Type" role="alert">
@if (!string.IsNullOrEmpty(Heading))
{
<h4 class="alert-heading">@Heading</h4>
}
<p>@ChildContent</p>
@if (Dismissible)
{
<button type="button" class="close" @onclick="Dismiss">
<span>×</span>
</button>
}
</div>
}
@code {
[Parameter]
public string Type { get; set; } = "info";
[Parameter]
public string Heading { get; set; }
[Parameter]
public RenderFragment ChildContent { get; set; }
[Parameter]
public bool Dismissible { get; set; } = false;
[Parameter]
public bool Show { get; set; } = true;
[Parameter]
public EventCallback<bool> ShowChanged { get; set; }
private async Task Dismiss()
{
Show = false;
await ShowChanged.InvokeAsync(false);
}
}
And you can easily use this component elsewhere:
<AlertComponent Type="warning" Heading="Warning!" Dismissible="true">
<p>This is an important message that users can dismiss.</p>
</AlertComponent>
State management in Blazor is versatile—you can handle it locally within components, pass it down using cascading parameters, or share it across components via dependency injection.
Real-World Success Stories
Enterprise Application Modernization
Imagine a financial services company that needed to modernize its legacy desktop software. They turned to Blazor because:
Their team already mastered C#, making the transition smooth
The application required complex calculations that benefited from a
unified language.
Integration with existing .NET libraries was a must.
They chose Blazor Server to leverage their existing infrastructure, ensuring sensitive operations stayed secure on the server. The end result was a modern, accessible web app that retained the power of their original desktop experience.
Progressive Web Applications in Healthcare
Another inspiring case comes from a healthcare provider that built a patient portal as a Progressive Web App (PWA) using Blazor WebAssembly. This approach enabled:
- Offline Access: Patients could view crucial information even without
an active internet connection.
- Native-Like Experience: The app felt smooth and responsive on mobile
devices.
- Enhanced Security: Client-side encryption kept patient data safe.
The use of service workers and local storage (like IndexedDB) ensured the app stayed fast and secure, even offline.
Best Practices When Building with Blazor
Here are some friendly tips to keep your Blazor apps running smoothly:
Performance Optimization:
- Virtualize Long Lists: Use the built-in `Virtualize` component to only render what's visible.
- Minimize Re-rendering: Leverage `@key` directives and override `ShouldRender()` when
needed.
- Code Splitting: Consider .NET Ahead-of-Time (AOT) compilation to reduce initial download
sizes.
Security Measures:
- Use robust authentication methods like ASP.NET Core Identity or third-party providers.
- Always perform server-side validations—don’t rely solely on client-side checks.
- Implement authorization on both ends to secure sensitive data.
Deployment Strategies:
- For Blazor WebAssembly, simply deploy your app as static files on a web server or CDN.
- For Blazor Server, deploy it as a standard ASP.NET Core app. For example, here’s a basic
Dockerfile setup:
FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443
FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
WORKDIR /src
COPY ["BlazorApp.csproj", "./"]
RUN dotnet restore "BlazorApp.csproj"
COPY . .
RUN dotnet build "BlazorApp.csproj" -c Release -o /app/build
FROM build AS publish
RUN dotnet publish "BlazorApp.csproj" -c Release -o /app/publish
FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "BlazorApp.dll"]
Wrapping Up
Blazor is more than just another framework—it’s a fresh take on building interactive, modern web applications. By letting you work in C# throughout your entire stack, it simplifies development and opens up new opportunities for both traditional .NET developers and those looking to explore innovative web technologies.
Whether you're modernizing an enterprise system or creating a slick, offline-capable PWA, Blazor’s flexibility in hosting (via WebAssembly or Server) and its powerful component model make it a strong candidate for your next project.
Frequently Asked Questions
- Can I mix Blazor Server and WebAssembly in one app? Absolutely. Using
hybrid approaches, you can start with Blazor Server for a quick load
and switch parts to WebAssembly for enhanced interactivity or offline
functionality.
- How does Blazor stack up against popular JavaScript frameworks?
Blazor Server offers fast load times similar to JavaScript
frameworks, although it may introduce slight delays during
interactions due to server round trips. Blazor WebAssembly might have
a larger initial download, but its performance for many operations is
comparable.
- Can I use my existing .NET libraries? Yes. Blazor Server can utilize
any compatible .NET library, and Blazor WebAssembly supports
libraries built for .NET Standard 2.0 or .NET 6+, though watch out
for any platform-specific dependencies.
- What about SEO for public-facing websites? Blazor Server naturally
renders on the server, which benefits SEO. Blazor WebAssembly apps
might need extra tweaks like server-side prerendering to optimize for
search engines.
- Is the Blazor ecosystem mature? While it's newer than frameworks like
React or Angular, the Blazor community is rapidly growing. Major UI
libraries (like those from Syncfusion, Telerik, and DevExpress) now
offer Blazor components, making it easier than ever to get started.