Trying to bind devxpress button.Enabled to an extended binding list property and it is not working-Collection of common programming errors

I have an extended binding list for my purposes:

public class MyList : BindingList, INotifyPropertyChanged
{
    private List invalidObjectsList;

    public MyList() : base()
    {
        invalidObjectsList = new List();
    }

    ...

    public bool IsValid 
    {
        get
        {
            return invalidObjectsList.Count == 0;
        }
    }

    ...

    // I have similar method for deletion
    AddElementToInvalidList(T element)
    {
        invalidObjectsList.Add(element);
        OnPropertyChanged("IsValid");
    }

    ...

    // Stuff for the INotifyPropertyChanged interface
    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = PropertyChanged;

        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }

    ...
}

I am designing the UI to be able to use that list to modify and save data to let’s say database. So in the UI I have a DevXpress button to “Save Data”. The actual list is assigned as dynamic, meaning:

dynamic list = DataProvider.GetObjectsList();

For that “Save data” button I am trying to bind it’s “Enabled” property to the “IsValid” property of my list as follows:

saveButton.DataBindings.Add("Enabled", list, "IsValid");

At run time I am getting unhandled Exception:

Cannot bind to the property or column IsValid on the DataSource.
Parameter name: dataMember

I can’t figure out what’s wrong here. Please, help.

Thanks in advance!