Since that class is nested within the View, you can just add access - exactly as you would any other C# class - e.g:
public class TableSource : MvxSimpleTableViewSource
{
private TwitterView _parent;
public TableSource (UITableView tableView, TwitterView parent)
: base(tableView, TweetCell3.Identifier, TweetCell3.Identifier)
{
_parent = parent;
tableView.RegisterNibForCellReuse(UINib.FromName(TweetCell3.Identifier, NSBundle.MainBundle), TweetCell3.Identifier);
}
public override float GetHeightForRow (UITableView tableView, NSIndexPath indexPath)
{
return _parent.SomeMethod(indexPath);
}
}