Creating Event Callbacks in C# Blazor

Event callbacks in C# Blazor allow you to handle events that occur in a Blazor component.

What is Blazor ?

Blazor is a web framework for building interactive client-side web applications using C# and .NET. It allows developers to use C# and .NET for building web applications, instead of JavaScript.

There are two main types of Blazor:

1. Blazor WebAssembly: runs client-side in a web browser via WebAssembly. This allows for C# code to run directly in the browser, without the need for a server-side component.
2. Blazor Server: runs on the server, and uses SignalR to communicate with the client. The client-side component is just a thin wrapper around the SignalR connection.

Blazor components are similar to React or Angular components, they are reusable and composable building blocks of an application, and they also can handle events and update the component’s state. It uses a component-based architecture, which allows developers to create reusable UI elements.

Blazor allows you to write rich interactive web UIs using C#, and it can access the DOM and JavaScript objects using JavaScript interop. It also has built-in support for dependency injection and a powerful routing system, making it easy to build complex web applications.

You can think of Blazor as a way to use C# to create web applications similar to how we use JavaScript, but with all the benefits of the .NET ecosystem.

Step to Create Event callbacks in C# Blazor

Event callbacks are a way to handle events that occur in a Blazor component. In this tutorial, I’ll show you how to create event callbacks in a C# Blazor project, step by step.

1. Create a new Blazor project in Visual Studio. You can do this by selecting "File" > "New" > "Project...", then selecting "Blazor App" from the list of templates. Give the project a name and click “Create.”
2. In the “Pages” folder, add a new Razor component called “ButtonEvent.razor.” This will be the component that we’ll use to demonstrate the event callback.
3. In the “ButtonEvent.razor” file, add a button element to the component’s markup:

<button @onclick="ButtonClicked">Click me!</button>

This button element has an @onclick attribute that specifies the name of the event callback function that should be called when the button is clicked.

4. In the “ButtonEvent.razor” file, add the following code to the component’s C# code block to define the ButtonClicked callback function:

private void ButtonClicked()
{
    Console.WriteLine("Button clicked!");
}

5. Run the project, navigate to the “ButtonEvent” page, and click the button. You should see the message “Button clicked!” printed in the browser’s developer console.
6. Now that we have the basics in place, you can build more logic in the callback functions like conditions and loops, also you can pass data from the event arguments that come from the DOM events to our callback function.

private void ButtonClicked(UIMouseEventArgs event)
{
    if (event.Button == 0)
    {
        Console.WriteLine("Left button clicked!");
    }
    else if (event.Button == 1)
    {
        Console.WriteLine("Middle button clicked!");
    }
    else
    {
        Console.WriteLine("Right button clicked!");
    }
}

That’s it! You’ve successfully created an event callback in a C# Blazor component. Event callbacks are a powerful feature that allows you to add interactivity and dynamic behavior to your Blazor components.

Also Read: Sanitize & Formatting Data in Laravel with Transformer Package

Advantage of Blazor

Blazor has several advantages that make it a compelling choice for building web applications:

1. Single Language: Blazor allows developers to build web applications using C# and .NET, instead of JavaScript. This means that you can use the same language and tooling for both the client and server sides of the application.
2. Reusability: Blazor’s component-based architecture allows developers to create reusable UI elements, which can be shared across different parts of the application. This can help improve code maintainability and reduce the amount of code you need to write.
3. Interoperability: Blazor provides built-in support for JavaScript interop, which allows developers to access JavaScript libraries and APIs from C# code. This enables developers to leverage existing JavaScript libraries in their Blazor applications.
4. Productivity: Blazor allows developers to use .NET’s rich ecosystem of libraries and frameworks, such as Entity Framework, ASP.NET Core, and the Azure SDK, to build web applications. This can increase developer productivity and accelerate the development process.
5. Development Experience: Blazor allows developers to leverage the same development experience that they are used to in .NET, using familiar tools and libraries such as Visual Studio and Visual Studio Code, also the debugging and profiling tools work seamlessly.
6. Flexibility: As Blazor has two hosting models, it offers more flexibility when choosing the best way to host a web application. Blazor WebAssembly allows the application to run client-side while Blazor Server allows the application to run server-side. This makes Blazor a great option for building web applications that can run on a variety of devices, including desktops, laptops, tablets, and smartphones.
7. Up to date: Blazor is continuously updated to use the most up-to-date version of .NET, this ensure that the development experience and performance of the app will improve as the technology evolves.
8. Community Support: Blazor is an open-source technology and its growing community which share their experiences, and created packages to help with common tasks. This community is helping to evolve the framework and provide good support to the users.