ASP.NET Core Blazor

Blazor Hosting Models

Blazor allows you to build interactive web UIs using C# and .NET instead of JavaScript. Blazor supports multiple hosting models, each with its own advantages and use cases. Understanding these models is crucial for selecting the best approach for your application.

Blazor Server

With Blazor Server, your C# code runs on the server. A JavaScript proxy on the client establishes a real-time connection with the server using SignalR. When UI events occur (e.g., a button click), the event is sent to the server. The server executes the event handler, computes the UI diff, and sends the diff back to the client for the JavaScript proxy to apply to the DOM.

Key Characteristics:

• Server-side execution: All .NET code runs on the server.
• Real-time connection: Requires a persistent SignalR connection.
• Fast initial load: The initial download is small as only UI marshaling code is sent.
• Access to server resources: Can directly access server-side APIs and data.
• Scalability concerns: Each active client holds a server connection, which can impact scalability.

Consider Blazor Server for internal business applications, content-driven sites where server interaction is frequent, or when you need to leverage server-side resources easily.

Blazor WebAssembly

Blazor WebAssembly (WASM) allows you to run your Blazor apps entirely in the browser. Your .NET code and the .NET runtime are compiled to WebAssembly, which can then be downloaded and executed by the browser. The UI is rendered directly in the browser's DOM.

Key Characteristics:

• Client-side execution: All .NET code runs in the browser.
• No persistent server connection required: After initial download, runs standalone.
• Larger initial download: The .NET runtime and app assemblies are downloaded to the browser.
• Offline support: Can function offline once downloaded.
• Limited browser APIs: Direct access to browser APIs can be more complex.

Blazor WebAssembly is ideal for rich client-side applications, public-facing websites, and scenarios where offline capabilities are important.

Blazor Hybrid

Blazor Hybrid allows you to embed Blazor web UI into native desktop or mobile applications. This is achieved by hosting Blazor components within a native app using a BlazorWebView component. This component hosts a web view control that loads your Blazor app. Your C# code runs on the native platform's .NET runtime, but the UI is rendered in the web view.

Key Characteristics:

• Native app integration: Ideal for existing desktop (WPF, WinForms) or mobile (MAUI) applications.
• Share code: Reuse Blazor components across web and native platforms.
• Access to native APIs: Can interact with native device features directly.
• Runs on native .NET: Utilizes the .NET runtime on the device.

Blazor Hybrid is perfect for developers looking to build cross-platform applications with a shared web UI codebase or to modernize existing desktop applications with modern web UI.

Choosing the Right Hosting Model

The choice of hosting model depends heavily on your application's requirements:

• Blazor Server: Prioritize server resources, fast initial load, and easy access to server-side APIs.
• Blazor WebAssembly: Need rich client-side interactivity, offline capabilities, or a standalone web application.
• Blazor Hybrid: Developing native desktop or mobile apps and want to leverage web UI skills and code sharing.

You can also combine these models within a single application, for instance, using Blazor WebAssembly for the client-side UI and calling server-side APIs.