Avalonia/src/Avalonia.Base/Input/Navigation/FocusExtensions.cs

namespace Avalonia.Input.Navigation
{
    /// <summary>
    /// Provides extension methods relating to control focus.
    /// </summary>
    internal static class FocusExtensions
    {
        /// <summary>
        /// Checks if the specified element can be focused.
        /// </summary>
        /// <param name="e">The element.</param>
        /// <returns>True if the element can be focused.</returns>
        public static bool CanFocus(this IInputElement e)
        {
            var visible = (e as Visual)?.IsVisible ?? true;
            return e.Focusable && e.IsEffectivelyEnabled && visible;
        }

        /// <summary>
        /// Checks if descendants of the specified element can be focused.
        /// </summary>
        /// <param name="e">The element.</param>
        /// <returns>True if descendants of the element can be focused.</returns>
        public static bool CanFocusDescendants(this IInputElement e)
        {
            var visible = (e as Visual)?.IsVisible ?? true;
            return e.IsEffectivelyEnabled && visible;
        }
    }
}