Shaker/Avalonia/Avalonia.Xaml.Interactions.Custom/Actions/FocusControlAction.cs

using Avalonia.Controls;
using Avalonia.Threading;
using Avalonia.Xaml.Interactivity;

namespace Avalonia.Xaml.Interactions.Custom;

/// <summary>
/// Focuses the associated or target control when executed.
/// </summary>
public class FocusControlAction : Avalonia.Xaml.Interactivity.Action
{
    /// <summary>
    /// Identifies the <seealso cref="TargetControl"/> avalonia property.
    /// </summary>
    public static readonly StyledProperty<Control?> TargetControlProperty =
        AvaloniaProperty.Register<FocusControlAction, Control?>(nameof(TargetControl));

    /// <summary>
    /// Gets or sets the target control. This is a avalonia property.
    /// </summary>
    [ResolveByName]
    public Control? TargetControl
    {
        get => GetValue(TargetControlProperty);
        set => SetValue(TargetControlProperty, value);
    }

    /// <summary>
    /// Executes the action.
    /// </summary>
    /// <param name="sender">The <see cref="object"/> that is passed to the action by the behavior. Generally this is <seealso cref="IBehavior.AssociatedObject"/> or a target object.</param>
    /// <param name="parameter">The value of this parameter is determined by the caller.</param>
    /// <returns>Returns null after executed.</returns>
    public override object? Execute(object? sender, object? parameter)
    {
        if (!IsEnabled)
        {
            return false;
        }

        var control = TargetControl ?? sender as Control;
        Dispatcher.UIThread.Post(() => control?.Focus());
        return null;
    }
}