[C# MSCE]读取未打开dgn中元素的材质

读写外部DGN文件有一定的复杂性，请参考如下帖子中的C++代码（和C#是类似的)

https://communities.bentley.com/communities/other_communities/chinafirst/f/microstation-projectwise/152695/msce-c-u6-dgn

需要调用两个关键的函数FillDictionaryModel和FillSectionsInModel

string file = @"C:\Users\Administrator\Desktop\测试图片.dgn";
            DgnDocument dgnDoc = DgnDocument.CreateForLocalFile(file);
            DgnFileOwner m_dgnFileOwner = DgnFile.Create(dgnDoc, DgnFileOpenMode.ReadWrite);
            DgnFile m_dgnFile = m_dgnFileOwner.DgnFile;
            StatusInt openForReadStatus;
            Bentley.DgnPlatformNET.DgnFileStatus status;
            if (DgnFileStatus.Success != (status = m_dgnFile.LoadDgnFile(out openForReadStatus)))
            {
                System.Windows.Forms.MessageBox.Show(status.ToString());
                return StatusInt.Error;
            }
            StatusInt suce = m_dgnFile.FillDictionaryModel();
            foreach (Bentley.DgnPlatformNET.ModelIndex index in m_dgnFile.GetModelIndexCollection())
            {
                ModelId ModelId = m_dgnFile.FindModelIdByName(index.Name);
                Bentley.DgnPlatformNET.StatusInt errorDetails;
                DgnModel model = m_dgnFile.LoadRootModelById(out errorDetails, ModelId, true, true, true);
                suce = m_dgnFile.FillSectionsInModel(model, DgnModelSections.Model);
                List<Bentley.DgnPlatformNET.Elements.Element> elemList = model.GetGraphicElements().ToList();
                foreach (Element el in elemList)
                {
                    if(el.ElementId== 73732)
                    {
                        MaterialSearchStatus searchStatus;
                        Material mat = MaterialManager.FindMaterialAttachment(out searchStatus, el, el.DgnModel, true);
                        if (searchStatus != MaterialSearchStatus.Success)
                        {
                            System.Windows.Forms.MessageBox.Show("失败");
                        }
                    }
                }
            }
            m_dgnFile.ProcessChanges(DgnSaveReason.FileClose);
            m_dgnFile.Release();

符老师  我添加了   还是不行   是不是材质还得初始化其他的？

不将文件作为当前文件打开确实会有许多影响。我们可以用排除法来诊断问题：

1. 从外部打开文件能否取得该元素的其他信息？不能，说明你的程序没有写对；能，说明你的程序可以操作外部文件中的元素了。
2. 将该文件作为当前文件打开，执行你的提取材质的代码是否正确？不正确，请修改提取材质代码。正确，则说明确实是从外部打开的方式下无法提取材质信息。

1.C#这段代码   打开的dgn和为打开的dgn都不能读到。（这代码就不能或得）

2.我看了论坛提到用实现接口 IElementGraphicsProcessor  中函数

virtual void _AnnounceElemMatSymb(ElemMatSymbCR  matSymb) override
 {
  m_MaterialCP = matSymb.GetMaterial();//获得元素的材质
 }

经测试  当前的打开的可以。但测试未打开的dgn得不到（加载dgn也加了符老师提的那几句关键代码），求符老师指条明路，如何得到未打开dgn材质

1.C#这段代码   打开的dgn和为打开的dgn都不能读到。（这代码就不能或得）

2.我看了论坛提到用实现接口 IElementGraphicsProcessor  中函数

virtual void _AnnounceElemMatSymb(ElemMatSymbCR  matSymb) override
 {
  m_MaterialCP = matSymb.GetMaterial();//获得元素的材质
 }

经测试  当前的打开的可以。但测试未打开的dgn得不到（加载dgn也加了符老师提的那几句关键代码），求符老师指条明路，如何得到未打开dgn材质

我写了一个测试代码测试了一下，可以从外部DGN中拿到元素的材质（Attached Material而非Assigned Material）。

public static void Material(string unparsed)
        {
            string strDgn = "c:\\111\\tu.dgn";
            DgnDocument dgnDoc = DgnDocument.CreateForLocalFile(strDgn);
            DgnFileOwner dgnFileOwner = DgnFile.Create(dgnDoc, DgnFileOpenMode.ReadOnly);
            DgnFile dgnFile = dgnFileOwner.DgnFile;
            StatusInt errorStatus;
            dgnFile.LoadDgnFile(out errorStatus);
            dgnFile.FillDictionaryModel();

            DgnModel dgnModel = dgnFile.LoadRootModelById(out errorStatus, dgnFile.DefaultModelId);
            dgnFile.FillSectionsInModel(dgnModel, DgnModelSections.All);
            Element myElem = dgnModel.FindElementById((ElementId)1295L);
            if (null == myElem)
            {
                MessageCenter.Instance.ShowInfoMessage("Can't find element which id=1295", null, true);
                return;
            }
            MaterialSearchStatus searchStatus;
            Material mat = MaterialManager.FindMaterialAttachment(out searchStatus, myElem, myElem.DgnModel, true);
            if (searchStatus != MaterialSearchStatus.Success)
            {
                MessageCenter.Instance.ShowInfoMessage("Failed in FindMaterialAttachment", null, true);
                return;
            }
            MessageCenter.Instance.ShowInfoMessage("Successful", null, true);
            dgnFile.Release();
        }

测试dgn如下：

tu.dgn

对于   Attached Material是可以， 并且用C++的 IElementGraphicsProcessor 接口也可以获得。但对于Assigned Material  用C++的 IElementGraphicsProcessor 接口就不能获得了。  推测是不是还需要初始化什么？  或者有其他方法获得？

下面代码可同时取得元素的两种材质名称。注意，我将Element改成了DisplayableElement，因为只有DisplayableElment才能取得颜色。

public static void Material(string unparsed)
        {
            string strDgn = "c:\\111\\tu.dgn";
            DgnDocument dgnDoc = DgnDocument.CreateForLocalFile(strDgn);
            DgnFileOwner dgnFileOwner = DgnFile.Create(dgnDoc, DgnFileOpenMode.ReadOnly);
            DgnFile dgnFile = dgnFileOwner.DgnFile;
            StatusInt errorStatus;
            dgnFile.LoadDgnFile(out errorStatus);
            dgnFile.FillDictionaryModel();

            DgnModel dgnModel = dgnFile.LoadRootModelById(out errorStatus, dgnFile.DefaultModelId);
            dgnFile.FillSectionsInModel(dgnModel, DgnModelSections.All);
            DisplayableElement myElem = dgnModel.FindElementById((ElementId)1295L) as DisplayableElement;
            if (null == myElem)
            {
                MessageCenter.Instance.ShowInfoMessage("Can't find element which id=1295", null, true);
                return;
            }
            string msg = null;
            MaterialSearchStatus searchStatus;
            Material matAttached = MaterialManager.FindMaterialAttachment(out searchStatus, myElem, myElem.DgnModel, true);
            if (searchStatus == MaterialSearchStatus.Success)
            {
                msg += "AttachedMaterialName=" + matAttached.Name;
            }
            uint color = myElem.GetElementDisplayParameters(true).LineColor;
            Material matAssigned = MaterialManager.FindMaterialBySymbology(out searchStatus, myElem.LevelId, color, dgnModel, false, true);
            if (searchStatus == MaterialSearchStatus.Success)
            {
                if (null != msg)
                    msg += ", ";
                msg += "AssignedMaterialName=" + matAssigned.Name;
            }
            if (null == msg)
                msg = "No Material";
            MessageCenter.Instance.ShowInfoMessage(msg, null, true);
            dgnFile.Release();
        }

public static void Material2(string unparsed)
        {
        
            Bentley.DgnPlatformNET.DgnModel dgnModel = Session.Instance.GetActiveDgnModel();
            Bentley.DgnPlatformNET.DgnFile dgnFile = Session.Instance.GetActiveDgnFile();
            //读取当前 model
            

            if (0 == dgnModel.GetElementCount(DgnModelSections.Model))
            {
                MessageCenter.Instance.ShowInfoMessage("未找到可读取元素！", null, true);
                return;
            }
            //判断是否为空
            
            ModelElementsCollection eles = Session.Instance.GetActiveDgnModel().GetGraphicElements();
            //读取图形元素个数
            foreach (Element ele in eles)
            {
                if (null == ele)
                {
                    MessageCenter.Instance.ShowInfoMessage("Can't find element which id=1746", null, true);
                    return;
                }
                string msg = null;
                MaterialSearchStatus searchStatus;
                
                Bentley.DgnPlatformNET.Material matAttached = MaterialManager.FindMaterialAttachment(out searchStatus, ele, ele.DgnModel, true);  //ele.DgnModelRef,
                if (searchStatus == MaterialSearchStatus.Success)
                {
                    msg += "AttachedMaterialName=" + matAttached.Name;
                }
                
                if (null == msg)
                    msg = "No Material";
                MessageCenter.Instance.ShowInfoMessage(msg, null, true);
            }
        }

符老师，我想使用您这个方法批量读取element，在打开当前dgn文档中使用，代码改写后，所有的结果都是No material，之前按照DisplayableElement转换myElem得到的结果都是null，能帮我看一下问题所在吗？

符老师，我说错了，很多element都是null，中间混杂着一些可以读取出的元素，这是什么原因啊？