WPF_Practice/PacticeSolution/CommandPatternSample/Command/RelayCommand.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace CommandPatternSample.Command
{
    internal class RelayCommand : ICommand
    {
        private Func<object, bool> _canExecute;
        private Action<object> _executeAction;

        public event EventHandler CanExecuteChanged;

        public RelayCommand(Action<object> executeAction, Func<object, bool> canExeute)
        {
            _executeAction = executeAction ?? throw new ArgumentNullException("Execute action is not null");
            _canExecute = canExeute;
        }

        public RelayCommand(Action<object> executeAction) : this(executeAction, null)
        {
            
        }

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

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