MARKUS

using System;

using System.Collections.Generic;

using System.Diagnostics.CodeAnalysis;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Input;

namespace Markus.Mvvm.ToolKit

{

    public class RelayCommand<T> : ICommand

    {

        private readonly Predicate<T> _canExecute;

        private readonly Action<T> _execute;

        public RelayCommand(Action<T> execute)

           : this(execute, null)

        {

            _execute = execute;

        }

        public RelayCommand(Action<T> execute, Predicate<T> canExecute)

        {

            if (execute == null)

            {

                throw new ArgumentNullException("execute");

            }

            _execute = execute;

            _canExecute = canExecute;

        }

        public bool CanExecute(object parameter)

        {

            return _canExecute == null || _canExecute((T)parameter);

        }

        public void Execute(object parameter)

        {

            _execute((T)parameter);

        }

        public event EventHandler CanExecuteChanged

        {

            add { CommandManager.RequerySuggested += value; }

            remove { CommandManager.RequerySuggested -= value; }

        }

    }

    public class RelayCommand : ICommand

    {

        private readonly Predicate<object> _canExecute;

        private readonly Action<object> _execute;

        public RelayCommand(Action<object> execute)

           : this(execute, null)

        {

            _execute = execute;

        }

        public RelayCommand(Action<object> execute, Predicate<object> canExecute)

        {

            if (execute == null)

            {

                throw new ArgumentNullException("execute");

            }

            _execute = execute;

            _canExecute = canExecute;

        }

        public bool CanExecute(object parameter)

        {

            return _canExecute == null || _canExecute(parameter);

        }

        public void Execute(object parameter)

        {

            _execute(parameter);

        }

        // Ensures WPF commanding infrastructure asks all RelayCommand objects whether their

        // associated views should be enabled whenever a command is invoked 

        public event EventHandler CanExecuteChanged

        {

            add

            {

                CommandManager.RequerySuggested += value;

                CanExecuteChangedInternal += value;

            }

            remove

            {

                CommandManager.RequerySuggested -= value;

                CanExecuteChangedInternal -= value;

            }

        }

        private event EventHandler CanExecuteChangedInternal;

        public void RaiseCanExecuteChanged()

        {

            CanExecuteChangedInternal.Raise(this);

        }

    }

}