等级库驱动设备在ClassEdit怎么配置才能读取等级库中尺寸信息

using Bentley.Building.Mechanical.ComponentLibrary.Common.DrawGeometry;
using Bentley.Building.Mechanical.ComponentLibrary.Equipment;
using Bentley.Building.Mechanical.Components;
using System.Collections.Generic;

namespace Wisdri.Building.Mechanical.ComponentLibrary.Equipment
{
class EQUIPTEST : BaseEquipment
{
protected double Length;
protected double Height;
protected double Thickness;
public EQUIPTEST()
{
_app = new BMApplication();
_fluidPorts = new List<Port>();
_placementPoints = new List<PlacementPoint>();
}

public override List<ElementHolder> Create3DElements()
{
List<ElementHolder> elements = new List<ElementHolder>();
Plate plate = new Plate(Length, Height, Thickness);
elements.AddRange(plate.Create3DElements());

BaseGeometry.SetSymbologyForElementTypes(elements, 0, -1, BMSymbolBasisType.EquipmentSymbology, _bmECObject);
return elements;
}

public override void Setup()
{
Length = _bmECObject.Instance["LEN"].DoubleValue;
Height = _bmECObject.Instance["HEI"].DoubleValue;
Thickness = _bmECObject.Instance["THK"].DoubleValue;
}
}

}

类设置与设备定义示例程序如上所示，但插入设备时，无法调用元件库中数据，而是直接以默认值0.0来绘制模型，可在绘制界面修改尺寸，但无法调用定义好的等级库