Silverlight View Model Style Popup

using System.Windows.Input;
using System;

// From http://johnpapa.net/silverlight/5-simple-steps-to-commanding-in-silverlight/
public class DelegateCommand : ICommand
{
    Func< object, bool > canExecute;
    Action< object > executeAction;
    bool canExecuteCache;

    public DelegateCommand(Action<object> executeAction, Func<object, bool> canExecute)
    {
        this.executeAction = executeAction;
        this.canExecute = canExecute;
    }

    #region ICommand Members

    public bool CanExecute(object parameter)
    {
        bool temp = canExecute(parameter);

        if (canExecuteCache != temp)
        {
            canExecuteCache = temp;
            if (CanExecuteChanged != null)
            {
                CanExecuteChanged(this, new EventArgs());
            }
        }

        return canExecuteCache;
    }

    public event EventHandler CanExecuteChanged;

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

    #endregion
}