private Boolean OnShouldReturn(UITextField field)
 {
     if (field.Tag == 1)
     {
         PasswordField.BecomeFirstResponder();
     }
     else
     {
         field.ResignFirstResponder();
     }
     return(false);
 }
 public override void RowSelected(UITableView tableView, NSIndexPath indexPath)
 {
     // Username field row
     if (indexPath.Section == 0 && indexPath.Row == 0)
     {
         UsernameField.BecomeFirstResponder();
     }
     // Password field row
     else if (indexPath.Section == 0 && indexPath.Row == 1)
     {
         PasswordField.BecomeFirstResponder();
     }
 }
 void UserNameField_EditingDidEndOnExit(object sender, EventArgs e)
 {
     PasswordField.BecomeFirstResponder();
 }