Web-Development-with-Blazor-Second-Edition/Chapter15/CustomElements/BlazorCustomElements/Counter.razor

<h1>Blazor counter</h1>

<p role="status">Current count: @currentCount</p>
<p>Increment amount: @IncrementAmount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {
    private int currentCount = 0;

    [Parameter] public int IncrementAmount { get; set; } = 1;

    private void IncrementCount()
    {
        currentCount += IncrementAmount;
    }
}