CommandManager.InvalidateRequerySuggested does not cause a requery on CanExecute in MVVM-Light

Just to add another possible solution, in my case I needed to call CommandManager.InvalidateRequerySuggested on the UI thread using Application.Current.Dispatcher.Invoke.

There are a lot suggestions out there (here, here, here).

I use a simple but not so beautiful workaround. I simply call OnPropertyChanged("MyICommand") for my commands in my BackgroundWorker Completed Event.

According to Josh Smith's article 'Allowing CommandManager to query your ICommand objects'. The problem is that the command is a non-routed command.

I have made a new implementation of the MVVM-Light RelayCommand as follows:

// original
//public event EventHandler CanExecuteChanged;


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

public void RaiseCanExecuteChanged()
{
    CommandManager.InvalidateRequerySuggested();
    //            var handler = CanExecuteChanged;
    //            if (handler != null)
    //            {
    //                handler(this, EventArgs.Empty);
    //            }
}