IWorkspaceFactory pWorkspaceFactory;
　　IFeatureWorkspace pFeatureWorkspace;
　　IFeatureLayer pFeatureLayer;
　　IFeatureDataset pFeatureDataset;
　　//打开CAD数据集
　　pWorkspaceFactory = new CadWorkspaceFactoryClass();
　　pFeatureWorkspace = (IFeatureWorkspace)pWorkspaceFactory.OpenFromFile(directoryPath, 0);
　　//打开一个要素集
　　pFeatureDataset = pFeatureWorkspace.OpenFeatureDataset(fileName);
　　//IFeaturClassContainer可以管理IFeatureDataset中的每个要素类
　　IFeatureClassContainer pFeatureClassContainer = (IFeatureClassContainer)pFeatureDataset;
　　//对CAD文件中的要素进行遍历处理
　　for (int i = 0; i < pFeatureClassContainer.ClassCount - 1; i++)
　　{
　　IFeatureClass pFeatureClass = pFeatureClassContainer.get_Class(i);
　　if (pFeatureClass.FeatureType == esriFeatureType.esriFTAnnotation)
　　{
　　//如果是注记，则添加注记层
　　pFeatureLayer = new CadAnnotationLayerClass();
　　}
　　else//如果是点、线、面，则添加要素层
　　{
　　pFeatureLayer = new FeatureLayerClass();
　　pFeatureLayer.Name = pFeatureClass.AliasName;
　　pFeatureLayer.FeatureClass = pFeatureClass;
　　this.axmc_Main.Map.AddLayer(pFeatureLayer);
　　this.axmc_Main.ActiveView.**();
　　}

　　}

　　方法二、直接打开CAD数据的点线面注记等要素类，所加载的数据均为一个独立的图层。

　具体代码如下:

CadWorkspaceFactoryClass fac=new CadWorkspaceFactoryClass ();
   String filePath="E:\cad";
   IFeatureWorkspace space=fac.OpenFromFile(filePath,0) as IFeatureWorkspace ;
   下面是打开FeatureClass的代码：
   //线
   IFeatureClass polyline =space.OpenFeatureClass("NewCAD.dwg:Polyline");  
   IFeatureLayer layer=new CadFeatureLayerClass ();
   layer.FeatureClass =polyline;
   //点
   IFeatureClass point=space.OpenFeatureClass ("NewCAD.dwg:Point");
   layer=new CadFeatureLayerClass ();
   layer.FeatureClass =point;
   //面  
   IFeatureClass polygon=space.OpenFeatureClass ("NewCAD.dwg:Polygon");
   ayer=new CadFeatureLayerClass();
   layer.FeatureClass =polygon;
   //注记  
   IFeatureClass anno=space.OpenFeatureClass ("NewCAD.dwg:Annotation");
   layer=new CadAnnotationLayerClass();
   layer.FeatureClass =anno;
//其实在Coverage文件的开发方式与Autocad方法类似,可以参考.

　　方法三、利用绘图空间直接加载CAD数据集，加载后各类型数据作为一个图层显示。

　　

　　IWorkspaceFactory pWorkspaceFactory = new CadWorkspaceFactoryClass();

　　IWorkspace pWorkspace = pWorkspaceFactory.OpenFromFile(directoryPath, 0);

　　//--定义一个CAD画图空间，并把上边打开的工作空间赋给它

　　ICadDrawingWorkspace pCadDrawingWorkspace = pWorkspace as ICadDrawingWorkspace;

　　//--定义一个CAD的画图数据集，并且打开上边指定的工作空间中一幅CAD图

　　//--然后赋值给CAD数据集

　　ICadDrawingDataset pCadDrawingDataset = pCadDrawingWorkspace.OpenCadDrawingDataset(fileName);

　　//--通过ICadLayer类，把上边得到的CAD数据局赋值给ICadLayer类对象的

　　//--CadDrawingDataset属性

　　ICadLayer pCadLayer = new CadLayerClass();

　　pCadLayer.CadDrawingDataset = pCadDrawingDataset;

　　//--利用MapControl加载CAD层

　　this.axmc_Main.Map.AddLayer(pCadLayer);
　　this.axmc_Main.ActiveView.**();

　　方法四、也是遍历CAD点线面，但是不用检查数据类型是否为注记。

　　IWorkspaceFactory pWorkspaceFactory = new CadWorkspaceFactoryClass();
　　IFeatureWorkspace pFeatureWorkspace = pWorkspaceFactory.OpenFromFile(directoryPath, 0) as IFeatureWorkspace;
　　IFeatureDataset pFeatureDataset = pFeatureWorkspace.OpenFeatureDataset(fileName);
　　IFeatureClassContainer pFeatureClassContainer = (IFeatureClassContainer)pFeatureDataset;
　　for (int i = 0; i < pFeatureClassContainer.ClassCount - 1; i++)
　　{
　　IFeatureClass pFeatureClass = pFeatureClassContainer.get_Class(i);
　　IFeatureLayer pFeatureLayer = new FeatureLayerClass();
　　pFeatureLayer.FeatureClass = pFeatureClass;
　　//ICadLayer pCadLayer = new CadLayerClass();
　　//pCadLayer = pFeatureLayer as ICadLayer;
　　this.axmc_Main.Map.AddLayer(pFeatureLayer);
　　this.axmc_Main.ActiveView.**();

　　}

　　方法五、类似与方法三。

　　//Add passed file to MapControl
　　ICadDrawingDataset pCadDrawingDataset = GetCadDrawingDataset(directoryPath, fileName);
　　if (pCadDrawingDataset == null) return;
　　ICadLayer pCadLayer = new CadLayerClass();
　　pCadLayer.CadDrawingDataset = pCadDrawingDataset;
　　pCadLayer.Name = fileName;
　　this.axmc_Main.AddLayer(pCadLayer, 0);

　　/// <summary>
　　/// 获取记录集
　　/// </summary>
　　/// <param name="directoryPath"></param>
　　/// <param name="fileName"></param>
　　/// <returns></returns>
　　private ICadDrawingDataset GetCadDrawingDataset(string directoryPath, string fileName)
　　{
　　//Create a WorkspaceName object
　　IWorkspaceName pWorkspaceName = new WorkspaceNameClass();
　　pWorkspaceName.WorkspaceFactoryProgID = "esriDataSourcesFile.CadWorkspaceFactory";
　　pWorkspaceName.PathName = directoryPath;
　　//Create a CadDrawingName object
　　IDatasetName pDatasetName = new CadDrawingNameClass();
　　pDatasetName.Name = fileName;
　　pDatasetName.WorkspaceName = pWorkspaceName;
　　//Open the CAD drawing
　　IName pName = (IName)pDatasetName;
　　return (ICadDrawingDataset)pName.Open();
　　}