private void OnMovePrevious(object sender, EventArgs e)
        {
            if (bindingSource != null)
            {
                bindingSource.MovePrevious();
            }

            OnRefreshItems();
        }
 /// <devdoc>
 ///     Navigates to previous item in BindingSource's list when the MovePreviousItem is clicked.
 /// </devdoc>
 private void OnMovePrevious(object sender, EventArgs e)
 {
     if (Validate())
     {
         if (bindingSource != null)
         {
             bindingSource.MovePrevious();
             RefreshItemsInternal();
         }
     }
 }