AvaloniaBehaviors

public class Command : ICommand
{
    private Action<object> _execute;
    private Predicate<object> _canExecute;

    public event EventHandler CanExecuteChanged;

    public Command(Action<object> execute = null, Predicate<object> canExecute = null)
    {
        _execute = execute;
        _canExecute = canExecute;
    }

    public virtual void NotifyCanExecuteChanged()
    {
        CanExecuteChanged?.Invoke(this, EventArgs.Empty);
    }

    public bool CanExecute(object parameter)
    {
        return _canExecute?.Invoke(parameter) ?? true;
    }

    public void Execute(object parameter)
    {
        _execute?.Invoke(parameter);
    }
}

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