private void HookCommand(ICommand command)
{
#if NET4
EventHandler handler = new EventHandler(OnCanExecuteChanged);
CommandHelpers.SetCanExecuteChangedHandler(this, handler);
command.CanExecuteChanged += handler;
#else
CanExecuteChangedEventManager.AddHandler(command, new EventHandler <EventArgs>(this.OnCanExecuteChanged));
#endif
this.UpdateCanExecute();
}
private void UnhookCommand(ICommand command)
{
#if NET4
var handler = CommandHelpers.GetCanExecuteChangedHandler(this);
if (handler != null)
{
command.CanExecuteChanged -= handler;
CommandHelpers.SetCanExecuteChangedHandler(this, null);
}
#else
CanExecuteChangedEventManager.RemoveHandler(command, new EventHandler <EventArgs>(this.OnCanExecuteChanged));
#endif
this.UpdateCanExecute();
}