endDrag(target) {
    if(!_drag) return false;

    //remove
    if(isNil(target)){
      _drag.remove();
      _selected.length = 0;
      this.refreshTable();
      return true;
    }

    //拖拽到它自己上，或者将其拖拽到自己的子节点上，直接返回
    if(target === _drag || target.parent === _drag) return false;

    var dragTarget;
    if(typeof _drag === 'string'){
      if(_drag === componentType.Text){
        dragTarget = FormElement.getTextElement();
      } else {
        var opts = getOptions(_drag);
        dragTarget = new FormElement(opts.name, opts);
      }
    } else {
      dragTarget = _drag;
    }

    dragTarget.remove();


    if(target.name === 'Col'){
      target.parent.addChild(getTarget(dragTarget, 'Col'), target.getIndex());
    } else if(target.name === 'Row'){
      target.addChild(getTarget(dragTarget, 'Col'));
    } else {
      target.addChild(getTarget(dragTarget, 'Row'));
    }
    this.refreshTable();
    return true;
  }
/*
  * @return indicate whether form changed.
  */
@return indicate whether form changed.
@return indicate whether form changed .
endDrag(target) {
    if(!_drag) return false;
    if(isNil(target)){
      _drag.remove();
      _selected.length = 0;
      this.refreshTable();
      return true;
    }
    if(target === _drag || target.parent === _drag) return false;
    var dragTarget;
    if(typeof _drag === 'string'){
      if(_drag === componentType.Text){
        dragTarget = FormElement.getTextElement();
      } else {
        var opts = getOptions(_drag);
        dragTarget = new FormElement(opts.name, opts);
      }
    } else {
      dragTarget = _drag;
    }
    dragTarget.remove();
    if(target.name === 'Col'){
      target.parent.addChild(getTarget(dragTarget, 'Col'), target.getIndex());
    } else if(target.name === 'Row'){
      target.addChild(getTarget(dragTarget, 'Col'));
    } else {
      target.addChild(getTarget(dragTarget, 'Row'));
    }
    this.refreshTable();
    return true;
  }
endDrag ( target ) { if ( ! _drag ) return false ; if ( isNil ( target ) ) { _drag . remove ( ) ; _selected . length = 0 ; this . refreshTable ( ) ; return true ; } if ( target === _drag || target . parent === _drag ) return false ; var dragTarget ; if ( typeof _drag === 'string' ) { if ( _drag === componentType . Text ) { dragTarget = FormElement . getTextElement ( ) ; } else { var opts = getOptions ( _drag ) ; dragTarget = new FormElement ( opts . name , opts ) ; } } else { dragTarget = _drag ; } dragTarget . remove ( ) ; if ( target . name === 'Col' ) { target . parent . addChild ( getTarget ( dragTarget , 'Col' ) , target . getIndex ( ) ) ; } else if ( target . name === 'Row' ) { target . addChild ( getTarget ( dragTarget , 'Col' ) ) ; } else { target . addChild ( getTarget ( dragTarget , 'Row' ) ) ; } this . refreshTable ( ) ; return true ; }
@return indicate whether form changed.
@return indicate whether form changed .
//remove //拖拽到它自己上，或者将其拖拽到自己的子节点上，直接返回