Blazor Tutorial Routing

What are the Route and Routing?

A Route is a URL pattern, and Routing is a pattern matching process that monitors the requests and determines what to do with each request.

• Blazor provides a client-side router.
• The Microsoft.AspNetCore.Blazor.Routing.Router class provides Routing in Blazor.
• In Blazor, the <Router> component enables routing, and a route template is provided to each accessible component.
• The <Router> component appears in the App.cshtml file.

<!--
    Configuring this here is temporary. Later we'll move the app config
    into Program.cs, and it won't be necessary to specify AppAssembly.
-->
<Router AppAssembly=typeof(Program).Assembly />

Route Templates

In Blazor, you define routes using route templates. You can define a route template by adding the @page directive to the top of a component.

@page "/"

<h1>Hello, world!</h1>

Welcome to your new app.

The above component would be loaded when the user navigated to www.mydomaim.com/

Multiple Routes

It is also valid to specify multiple route templates for a component. You can achieve this by defining multiple @page directives.

@page "/"
@page "/index"

<h1>Hello, world!</h1>

Welcome to your new app.

The above component would be loaded when the user navigated to www.mydomaim.com/ or www.mydomaim.com/index.

Define Route for pure C# Component

If you are defining your component as a pure C# class, then you can specify its route template by decorating it with the route attribute.

[Route("/counter")]
public class CounterClass : BlazorComponent
{
    // code here
}

It is ultimately what the @page directive gets compiled to.

• When a *.cshtml file with an @page directive is compiled, the generated class is given a RouteAttribute specifying the route template.
• At runtime, the router looks for component classes with a RouteAttribute and renders whichever component has a route template that matches the requested URL.

Route parameters

The Blazor client-side router uses route parameters to populate the corresponding component parameters with the same name (case insensitive).

@page "/route-parameter"
@page "/route-parameter/{text}"

<h1>Blazor is @Text!</h1>

@functions {
    [Parameter]
    private string Text { get; set; } = "awesome";
}

Optional parameters aren't supported yet, so two @page directives are applied in the above example.

The first @page directive permits navigation to the component without a parameter.

The second @page directive takes the {text} route parameter and assigns the value to the Text property.