Blazor Explained: A Practical Overview for Modern .NET Web Applications

Blazor supports multiple rendering approaches, allowing teams to choose the right balance between performance, SEO, scalability, and user experience.

Static Server Rendering (Static SSR)
HTML is generated on the server and sent to the client as a fully rendered page. The page is not interactive — no WebAssembly and no WebSockets are used.
This mode delivers extremely fast load times and is highly SEO-friendly, making it ideal for content-driven pages and public websites.

Interactive Server
The UI is rendered on the server while user interactions are handled in real time via SignalR (WebSockets). Application logic remains centralized on the server, reducing client-side complexity.
This approach is well suited for internal tools, dashboards, and applications with strict security requirements.

Interactive WebAssembly
The application runs directly in the browser using WebAssembly. After the initial download, it can run offline, offering a rich client-side experience.
This mode reduces server load and is ideal for highly interactive applications.

Interactive Auto
A hybrid approach that combines server-side rendering and WebAssembly. The first visit uses server rendering for fast initial load, while the WebAssembly bundle is downloaded in the background. Subsequent visits run fully client-side.

Blazor includes several techniques to improve perceived performance and user experience.

Static Server Rendering as a baseline
Static SSR is the default in modern Blazor templates, ensuring fast first paint and strong SEO performance.

Prerendering
For interactive modes, prerendering sends initial HTML immediately, avoiding blank screens while WebAssembly or SignalR initializes in the background.

Stream Rendering
Stream rendering allows parts of a page (such as layout or headers) to be rendered immediately, while the rest of the content loads asynchronously. Once the data is ready, Blazor streams the remaining HTML into the page.
This behavior is enabled using the [StreamRendering] attribute.

Enhanced Navigation
Even in Static SSR mode, Blazor can intercept link clicks and fetch only updated content instead of reloading the entire page. This delivers an SPA-like experience without JavaScript or WebAssembly.

Blazor uses an integrated router to map URLs directly to components.

Routing is managed by the <Router /> component in App.razor. Individual components define their routes using the @page directive, while rendering behavior can be controlled with the @rendermode directive at the page or component level.

Shared namespaces are handled through _Imports.razor, keeping component files clean and consistent.

🖱️ Events and User Interactions

Blazor maps standard DOM events directly to C# methods, enabling interaction handling without JavaScript.

Event handlers can accept typed arguments such as MouseEventArgs, KeyboardEventArgs, or ChangeEventArgs. Asynchronous handlers (async Task) are fully supported, and Blazor automatically updates the UI after execution.

Event modifiers like preventDefault and stopPropagation provide fine-grained control over browser behavior when needed.

🔁 Data Binding

Blazor supports two-way data binding, synchronizing UI values with C# variables automatically.

By default, values update on change, but bindings can be configured to react to every keystroke or execute logic immediately after updates. This significantly reduces boilerplate code and improves maintainability, especially in form-heavy applications.

🏗️ Blazor Web App Project Structure

Modern Blazor solutions typically consist of two main projects:

• Server project
  Contains server-side logic, APIs, and Static SSR pages.
• Client project (.Client)
  Contains components intended for WebAssembly or Interactive Auto rendering modes.

This structure supports scalability and a clear separation of responsibilities.

📊 Working with Data and Forms

Blazor offers robust components for data-driven UI.

QuickGrid
A modern, high-performance table component supporting sorting, filtering, and pagination. It requires the Microsoft.AspNetCore.Components.QuickGrid NuGet package and is suitable for enterprise-scale data views.

Forms and validation
The EditForm component simplifies form handling with strongly typed models and built-in validation. Validation messages can be displayed globally or per field, improving user experience and data quality.

🧩 Advanced Component Concepts

Blazor allows components to receive UI fragments as parameters using RenderFragment, enabling flexible layouts and reusable templates.

For larger projects, the code-behind pattern separates UI and logic by moving C# code into a .razor.cs partial class, improving readability and long-term maintainability.

🔌 JavaScript Interoperability

Blazor provides seamless interoperability between C# and JavaScript.

C# can call JavaScript functions with or without return values, while JavaScript can invoke both static and instance C# methods. Instance calls require passing an object reference explicitly.

JavaScript isolation allows scripts to be loaded as modules only for specific components, reducing global scope usage and improving performance.

🎯 Component and Element References

Using the @ref directive, Blazor enables direct access to DOM elements or component instances.

This is useful for scenarios such as focus management, imperative APIs, or advanced JavaScript interop.

✅ Best Practices for Production Applications

For scalable and maintainable applications, several best practices should be followed:

• Use EventCallback for child-to-parent communication
• Avoid static variables for user-specific state, especially in server-rendered apps
• Store user state in scoped services
• Properly dispose of resources by implementing IDisposable or IAsyncDisposable
  
  

🧭 Advanced Navigation Scenarios

Blazor provides the NavigationManager service for programmatic navigation and working with query strings.

The NavLink component replaces standard anchor tags and automatically applies active CSS classes based on URL matching. Route parameters can be defined directly in the @page directive and accessed via component parameters.

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