SpdUp/Core/RelayCommand.cs

using System.Windows.Input;

namespace SpdUp.Core;

/// <summary>
/// A basic ICommand implementation that delegates to Action/Func.
/// </summary>
public sealed class RelayCommand : ICommand
{
    private readonly Action<object?> _execute;
    private readonly Func<object?, bool>? _canExecute;

    public RelayCommand(Action<object?> execute, Func<object?, bool>? canExecute = null)
    {
        _execute = execute ?? throw new ArgumentNullException(nameof(execute));
        _canExecute = canExecute;
    }

    public RelayCommand(Action execute, Func<bool>? canExecute = null)
        : this(_ => execute(), canExecute is null ? null : _ => canExecute()) { }

    public event EventHandler? CanExecuteChanged
    {
        add => CommandManager.RequerySuggested += value;
        remove => CommandManager.RequerySuggested -= value;
    }

    public bool CanExecute(object? parameter) => _canExecute?.Invoke(parameter) ?? true;
    public void Execute(object? parameter) => _execute(parameter);

    public void RaiseCanExecuteChanged() => CommandManager.InvalidateRequerySuggested();
}

/// <summary>
/// Typed relay command.
/// </summary>
public sealed class RelayCommand<T> : ICommand
{
    private readonly Action<T?> _execute;
    private readonly Func<T?, bool>? _canExecute;

    public RelayCommand(Action<T?> execute, Func<T?, bool>? canExecute = null)
    {
        _execute = execute ?? throw new ArgumentNullException(nameof(execute));
        _canExecute = canExecute;
    }

    public event EventHandler? CanExecuteChanged
    {
        add => CommandManager.RequerySuggested += value;
        remove => CommandManager.RequerySuggested -= value;
    }

    public bool CanExecute(object? parameter) => _canExecute?.Invoke((T?)parameter) ?? true;
    public void Execute(object? parameter) => _execute((T?)parameter);
}