RelayCommand

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Windows.Input;

namespace AppCode.MVVM
{
	public class RelayCommand : ICommand, IRelayCommand
	{
		#region Fields

		readonly Action<object> _execute;
		readonly Predicate<object> _canExecute;

		#endregion

		#region Constructors

		/// <summary>
		/// Creates a new command that can always execute.
		/// </summary>
		/// <param name="execute">The execution logic.</param>
		public RelayCommand(Action<object> execute) : this(execute, null)
		{
		}

		/// <summary>
		/// Creates a new command.
		/// </summary>
		/// <param name="execute">The execution logic.</param>
		/// <param name="canExecute">The execution status logic.</param>
		public RelayCommand(Action<object> execute, Predicate<object> canExecute)
		{
			if (execute == null)
				throw new ArgumentNullException("execute");

			_execute = execute;
			_canExecute = canExecute;
		}

		#endregion

		#region ICommand Members

		[DebuggerStepThrough()]
		public bool CanExecute(object parameter)
		{
			return _canExecute == null ? true : _canExecute(parameter);
		}

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

		public void Execute(object parameter)
		{
			_execute(parameter);
		}

		#endregion
	}

}