# Component Properties

When creating a component you almost always need to pass props (or parameters/property values) to customize its appearance or behavior. In MauiReactor you can use plain properties.

Take for example this component that implements an activity indicator with a label:

```csharp
partial class BusyComponent : Component
{
    [Prop]
    string _message;
    [Prop]
    bool _isBusy;
    
    public override VisualNode Render()
     => StackLayout(
            ActivityIndicator()
                .IsRunning(_isBusy),
            Label()
                .Text(_message)
        );
}
```

and this is how we can use it on a page:

```csharp
class BusyPageState : IState
{
    public bool IsBusy { get; set; }
}

class BusyPageComponent : Component<BusyPageState>
{
    protected override void OnMounted()
    {
        SetState(_ => _.IsBusy = true);

        //OnMounted is called on UI Thread, move the slow code to a background thread
        Task.Run(async () =>
        {
            //Simulate lenghty work
            await Task.Delay(3000);

            SetState(_ => _.IsBusy = false);
        });

        base.OnMounted();
    }

    public override VisualNode Render()
      => ContentPage(
            State.IsBusy ?
            new BusyComponent()
                .Message("Loading")
                .IsBusy(true)
            :
            RenderPage()
        );

    private VisualNode RenderPage()
        => Label("Done!")
            .Center();
}
```

{% hint style="info" %}
If you need to set properties of components hosted on a different page you should use a Props object (see [Navigation](/mauireactor/components/navigation/navigation.md))
{% endhint %}


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