Introduction to Blazor

Learning objectives#

• Explain what Blazor is and where it fits
• Create and run a Blazor Web App
• Read a simple Razor component
• Compare Blazor with JavaScript frameworks

Explanation#

Blazor is part of ASP.NET Core. You build UI from Razor components: .razor files that mix HTML markup with C# code.

Components can render on the server (static or interactive over a SignalR connection) or run in the browser on WebAssembly. Since .NET 8 one Blazor Web App template supports all of these, chosen per page or component.

Because the same C# runs everywhere, you can share models, validation rules and services between the API and the UI.

Blazor suits teams that already know C#/.NET. React and Angular have larger ecosystems; Blazor wins on code sharing and tooling consistency.

Code example: Your first component#

1@* dotnet new blazor -o ShopUi --interactivity Server && cd ShopUi && dotnet watch *@
2@page "/hello"
3@rendermode InteractiveServer
4

5<h1>Namaste, @name!</h1>
6<input @bind="name" @bind:event="oninput" placeholder="Your name" />
7<p>You typed @name.Length characters.</p>
8

9@code {
10    private string name = "Techie Babaji";
11}

At /hello the heading updates on every keystroke: typing “Asha” shows “Namaste, Asha!” and “You typed 4 characters.”

This example is illustrative. Copy or download it and run it in your own environment; the expected output is shown above.

Step-by-step explanation#

1. dotnet new blazor creates a Blazor Web App; --interactivity Server enables interactive server rendering.
2. @page makes the component reachable at /hello.
3. @rendermode InteractiveServer makes it respond to events.
4. @bind keeps the input and the name field in sync; the markup re-renders automatically.

Real-world use case#

Common mistakes#

Best practices#

• Start with the Blazor Web App template
• Choose a render mode deliberately per page
• Keep components small and focused
• Use dotnet watch for hot reload

Remember this#

Practice exercise#

1<button @onclick="() => name = string.Empty">Clear</button>

Mini quiz#

Want more? Practise all Blazor MCQs · Blazor interview questions

Related topics#

My notes#

Saved in this browser.