1     class TlsApplication : IExtensionApplication //程序初始化，在加载dll时，cad会自动捕捉并运行该过程

  3     { 
  5         void IExtensionApplication.Initialize() 
  7         { 
  9             TTest.Start(); 
 11         } 
 13         void IExtensionApplication.Terminate() 
 15         { 
 17         } 
 19     }
 20 
 21     class TTest 
 23     { 
 25         static bool m_Veto = false; 
 27         public static void Start() 
 29         { 
 31             Application.DocumentManager.DocumentLockModeChanged += new DocumentLockModeChangedEventHandler(vetoCommand); 
 33             Application.BeginDoubleClick += new BeginDoubleClickEventHandler(beginDoubleClick); 
 35         } 
 37         static void beginDoubleClick(object sender, BeginDoubleClickEventArgs e) 
 39         { 
 41             Document doc = Application.DocumentManager.MdiActiveDocument; 
 43             Editor ed = doc.Editor; 
 45             PromptSelectionResult res = ed.SelectImplied(); 
 47             SelectionSet ss = res.Value; 
 49             if (ss != null) 
 51             { 
 53                 if (ss.Count == 1) 
 55                 { 
 57                     using (Transaction tr = doc.TransactionManager.StartTransaction()) 
 59                     { 
 61                         Line line = tr.GetObject(ss[0].ObjectId, OpenMode.ForRead) as Line; 
 63                         if (line != null) 
 65                         { 
 67                             ResultBuffer rb = line.GetXDataForApplication("MyApp"); //提取对象的扩展数据
 69                             if (rb != null) 
 71                             { 
 73                                 m_Veto = true; 
 75                             } 
 77                         } 
 79                     } 
 81                 } 
 83             } 
 85         }
 86 
 87         static void vetoCommand(object sender, DocumentLockModeChangedEventArgs e) 
 89         { 
 91             if (e.GlobalCommandName.ToLower() == "properties") //判断是否是调用属性对话框
 93             { 
 95                 if (m_Veto) 
 97                 {
 99                     e.Veto(); 
103                     Application.ShowAlertDialog("hello"); //在此处可以添加自定义对话框
105                     m_Veto = false; 
107                 } 
109             } 
111         } 
113     }