docs: public int controlToField()
      {
          int iErrorCode = Constant.NORMAL_RETURN;
          if ((this.getScreenFieldView().getControl() != null) && (this.getConverter() != null))
          {
              Object objValue = this.getScreenFieldView().getComponentState(this.getScreenFieldView().getControl());
              iErrorCode = this.getScreenFieldView().setFieldState(objValue, Constant.DISPLAY, Constant.SCREEN_MOVE);
          }
          return iErrorCode;
      }