[MSCE C#]单元中的子对象添加属性，会崩溃

Question

///

/// 给单元对象的子对象添加自定义属性 ///

/// private void AddCellChildProperty(CellHeaderElement cellEl) { ChildElementCollection elements = cellEl.GetChildren(); foreach (var el in elements) { var itemlibrary = ItemTypeLibrary.FindByName("库名1", Session.Instance.GetActiveDgnFile()); var itemType = itemlibrary.GetItemTypeByName("属性类型"); var host = new CustomItemHost(el, true); var instance = host.GetCustomItem("库名1", "属性类型"); if (null == instance) { instance = host.ApplyCustomItem(itemType); } instance.IsReadOnly = true; // instance.WriteChanges(); instance.ScheduleChanges(el); el.ReplaceInModel(el);//崩溃 cellEl.ReplaceInModel(el);//也会崩溃 } }

Yongan.Fu · Answer

如下测试代码可以正确执行： 
 using BIM = Bentley.Interop.MicroStationDGN;
using BMI = Bentley.MstnPlatformNET.InteropServices;
...
...
 private static void AddItemToChildInCell()
 {
 BIM.Application app = BMI.Utilities.ComApp;
 BIM.CellElement myCell = app.ActiveModelReference.GetElementByID64(11389L) as BIM.CellElement;
 myCell.ResetElementEnumeration();
 int nestDepth = 0;
 while (myCell.MoveToNextElement(true, ref nestDepth))
 {
 BIM.Element tempEl = myCell.CopyCurrentElement();
 if (tempEl.IsEllipseElement())
 {
 BIM.ItemTypeLibraries itemTypeLibraries = new BIM.ItemTypeLibrariesClass();
 BIM.ItemTypeLibrary itemTypeLib = itemTypeLibraries.FindByName("MyLib");
 BIM.ItemType itemType = itemTypeLib.GetItemTypeByName("MyType");
 itemType.AttachItem(tempEl);
 myCell.ReplaceCurrentElement(tempEl);
 }
 }
 myCell.Rewrite();
 } 
 我用了系统标准的单元库中的NORTH单元，该单元里面只有一个文字和一个圆。我的代码仅对圆这个子元素挂了我自定义的一个ItemType。 
 
 MS 学习资源： 
 MicroStation Wednesday 视频分享 
 深入探讨 MicroStation DGN 基本概念系列 
 一步步学习MicroStation CE Addin开发 
 一步步学习MicroStation CE MDL开发