Keep Your User Interface Responsive Easily Using a Coworker

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

namespace AsyncModel
{
    /// <summary>
    /// A ICommand implementation that invokes an arbitrary method within a Coworker.SyncBlock to allow
    /// code not blocking the user interface to be run within Coworker.AsyncBlocks.
    /// </summary>
    public class SyncBlockCommand : ICommand
    {
        private readonly Action action;

        private bool isRunning;

        public SyncBlockCommand(Action action)
        {
            this.action = action;
        }

        #region ICommand Members

        public bool CanExecute(object parameter)
        {
            return !isRunning;
        }

        public event EventHandler CanExecuteChanged;

        private void RaiseCanExecuteChanged()
        {
            EventHandler eh = CanExecuteChanged;
            if( eh != null )
            {
                eh(this, EventArgs.Empty);
            }
        }

        public void Execute(object parameter)
        {
            if (CanExecute(parameter))
            {
                isRunning = true;
                RaiseCanExecuteChanged();
                Coworker.SyncBlock(() =>
                {
                    try
                    {
                        action();
                    }
                    finally
                    {
                        isRunning = false;
                        RaiseCanExecuteChanged();
                    }
                });
            }
        }

        #endregion
    }
}