RelayCommand.cs

using System;
using System.Diagnostics;
using System.Windows.Input;

namespace Immutable_Deque_visualization
{
    // from http://msdn.microsoft.com/en-us/magazine/dd419663.aspx
    public class RelayCommand : ICommand
    {
        #region Fields

        readonly Action<object> m_execute;
        readonly Predicate<object> m_canExecute;

        #endregion // Fields

        #region Constructors

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

        public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)
        {
            if (execute == null)
                throw new ArgumentNullException("execute");

            m_execute = execute;
            m_canExecute = canExecute;
        }
        #endregion // Constructors

        #region ICommand Members

        [DebuggerStepThrough]
        public bool CanExecute(object parameter)
        {
            return m_canExecute == null || m_canExecute(parameter);
        }

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

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

        #endregion // ICommand Members
    }
}