The Blazor Puzzle: Puzzle 32 – Updating Parameters

Blazor is a popular framework for building interactive web applications using C# and .NET. In Blazor, components can communicate with each other by passing parameters. In this puzzle, we will explore how to update parameters in Blazor components.

Scenario:

Imagine you have a parent component that contains a child component. The child component has a parameter called “count” that determines the number of items to display. You want the parent component to update the “count” parameter of the child component based on user input.

Solution:

In order to update parameters in Blazor components, you can use event callbacks. Here’s how you can achieve this:

• Define a parameter in the parent component that will hold the updated value.
• Create a method in the parent component that updates the parameter value.
• Pass the method as an event callback to the child component.
• In the child component, invoke the event callback with the updated value.

Code Example:

        
// ParentComponent.razor
@page "/parent"
@using Microsoft.AspNetCore.Components

Parent Component
Enter the number of items to display:







@code {
    int newCount;

    void UpdateCount(int value)
    {
        newCount = value;
    }
}

// ChildComponent.razor
@using Microsoft.AspNetCore.Components

Child Component
Displaying @Count items

@code {
    [Parameter]
    public int Count { get; set; }

    [Parameter]
    public EventCallback UpdateCount { get; set; }
}
        
    

By following these steps and using event callbacks, you can easily update parameters in Blazor components and create dynamic and interactive web applications. Happy coding!