diff --git a/src/IFoxCAD.Cad/ExtensionMethod/XrefEx.cs b/src/IFoxCAD.Cad/ExtensionMethod/XrefEx.cs
new file mode 100644
index 0000000000000000000000000000000000000000..2a39873e974aac01bf54b965c9aa4d23ed66157f
--- /dev/null
+++ b/src/IFoxCAD.Cad/ExtensionMethod/XrefEx.cs
@@ -0,0 +1,492 @@
+namespace IFoxCAD.Cad;
+//对XBindXrefs,BindXrefs双重绑定参照释义的具体解析详个人第一原创的博客随笔
+//<a href="CAD.NET中使用XBindXrefs,BindXrefs双重绑定参照的探讨" https://www.cnblogs.com/SHUN-ONCET/p/16593360.html/>
+
+/// <summary>
+/// 表示累计要绑定符号表类型数量的枚举
+/// 最小为0,最大为4
+/// 具体【0为"图层表",1为"文字样式表",2为"标注样式表",3为"线型表",4为"注册应用程序表"】
+/// 如选择TextStyleTable = 1,则表示累计要绑定图层表和文字样式表,以此类推
+/// </summary>
+public enum XrefSymTabTypeNum
+{
+    /// <summary>
+    /// 图层表,"无敌绑定"项
+    /// </summary>
+    LayerTable = 0,
+    /// <summary>
+    /// 文字样式表
+    /// </summary>
+    TextStyleTable = 1,
+    /// <summary>
+    /// 标注样式表
+    /// </summary>
+    DimStyleTable = 2,
+    /// <summary>
+    /// 线性表
+    /// </summary>
+    LinetypeTable = 3,
+    /// <summary>
+    /// 注册应用程序表
+    /// </summary>
+    RegAppTable = 4
+}
+
+/// <summary>
+/// 双重绑定参照扩展类
+/// <summary>
+public static class XrefEx
+{
+    /// <summary>
+    /// 利用两个原生方法双重绑定参照
+    /// 可内部删除被卸载的嵌套参照
+    /// 该方法仅用于"无敌绑定"项,其他项有异常eWasOpenForNotify
+    /// </summary>
+    /// <param name="db">数据库</param>
+    /// <param name="isEaseNested">询问是否删除被卸载的嵌套参照,默认为true
+    /// 主要用于处理要绑定图纸中存在嵌套参照被卸载的情况
+    /// 若为false,则嵌套参照将被重载绑定后保留在图纸中</param>
+    /// <returns>无返回值</returns>
+    public static void XBindXrefs(Database db, bool isEaseNested = true)
+    {
+        var workingDb = HostApplicationServices.WorkingDatabase;//数据库转换
+        HostApplicationServices.WorkingDatabase = db;//数据库转换
+
+        db.ResolveXrefs(false, false);//解析数据库
+        
+        var bindXrefsIds = new ObjectIdCollection();//要BindXrefs的集合
+        var xBindXrefsIds = new ObjectIdCollection();//要XBindXrefs的集合
+
+        var isNestedNodeNameList = new List<string>();//要处理的嵌套参照名称列表
+        var isNestedIds = new ObjectIdCollection();//要处理的嵌套参照ObjectId集合
+
+        using (var tr = db.TransactionManager.StartTransaction())
+        {
+            #region 原块表参照的id集合获取
+            var bt = (BlockTable)tr.GetObject(db.BlockTableId, OpenMode.ForRead);//块表
+            foreach (ObjectId id in bt)
+            {
+                var btr = (BlockTableRecord)tr.GetObject(id, OpenMode.ForRead);
+                if (btr.IsFromExternalReference && btr.IsResolved)
+                    bindXrefsIds.Add(id);
+            }
+            #endregion
+
+            #region 补充是否被嵌套卸载的处理
+            XrefGraph xg = db.GetHostDwgXrefGraph(true);
+            int xrefcount = xg.NumNodes;
+            for (int j = 0; j < xrefcount; j++)
+            {
+                XrefGraphNode xrNode = xg.GetXrefNode(j);
+                if (xrNode.XrefStatus == XrefStatus.Unloaded)//若文件已卸载
+                {
+                    ObjectId deTachId = xrNode.BlockTableRecordId;
+                    BlockTableRecord btr = (BlockTableRecord)tr.GetObject(deTachId, OpenMode.ForRead);
+                    if (btr.IsFromExternalReference)
+                    {
+                        if (!xrNode.IsNested)//若为非嵌套参照
+                        {
+                            db.DetachXref(deTachId);//拆离已经卸载的非嵌套文件
+                        }
+                        else//若为嵌套参照
+                        {
+                            isNestedIds.Add(deTachId);
+                            isNestedNodeNameList.Add(xrNode.Name);//有嵌套参照，添加名称进列表，以供绑定后是否做删除处理
+                        }
+                    }
+                }
+                if (xrNode.XrefStatus == XrefStatus.Unreferenced)//若文件未参照
+                {
+                    db.DetachXref(xrNode.BlockTableRecordId);//拆离未参照的文件
+                }
+                #region 使用此方法添加的xrNode.BlockTableRecordId，绑定中会随机出现异常（勿用）
+                //if (xrNode.XrefStatus == XrefStatus.Resolved)//若文件已解析
+                //{
+                //    ObjectId bindXrefId = xrNode.BlockTableRecordId;
+                //    BlockTableRecord btr = (BlockTableRecord)tr.GetObject(bindXrefId, OpenMode.ForRead);
+                //    if (btr.IsFromExternalReference)
+                //    {
+                //       xrefIds.Add(bindXrefId);
+                //    }
+                //}
+                #endregion
+            }
+            #endregion
+
+            #region "无敌绑定"项
+            LayerTable layert = tr.GetObject(db.LayerTableId, OpenMode.ForRead) as LayerTable;//图层表
+            foreach (ObjectId id in layert)
+            {
+                LayerTableRecord ltr = (LayerTableRecord)tr.GetObject(id, OpenMode.ForRead);
+                if (ltr.IsResolved)
+                {
+                    xBindXrefsIds.Add(ltr.ObjectId);
+                }
+            }
+            #endregion
+
+            if (isNestedIds.Count > 0)//若有嵌套参照被卸载，重载
+            {
+                db.ReloadXrefs(isNestedIds);
+            }
+
+            #region 此处即为二者结合使用，且顺序非常重要。若交换秩序，则会绑定无效，切勿交换
+            db.XBindXrefs(xBindXrefsIds, true);//建议为true
+            db.BindXrefs(bindXrefsIds, true);//建议为true
+            #endregion
+
+            #region 内部删除嵌套参照的块操作
+            if (isEaseNested)
+            {
+                if (isNestedNodeNameList.Count > 0 && isNestedNodeNameList != null)
+                {
+                    isNestedNodeNameList.ForEach(blockName =>
+                    {
+                        if (bt.Has(blockName))
+                        {
+                            BlockTableRecord btr = (BlockTableRecord)tr.GetObject(bt[blockName], OpenMode.ForWrite);
+                            if (btr != null)
+                            {
+                                btr.Erase();
+                            }
+                        }
+                    });
+                }
+            }
+            #endregion
+        }
+        HostApplicationServices.WorkingDatabase = workingDb;//数据库转换
+    }
+    /// <summary>
+    /// 利用两个原生方法双重绑定参照
+    /// 1.增加绑定符号表累计的选择,LayerTable=0时,即单选图层表为"无敌绑定"项
+    /// 2.增加储存被卸载嵌套参照名称及句柄的字典,以ref方式传出方法
+    /// 提供外部处理嵌套参照的数据,绑定后若不处理,则将被保留在图纸中
+    /// </summary>
+    /// <param name="db">数据库</param>
+    /// <param name="isNestedNodeNameDic">储存被卸载嵌套参照名称及句柄的字典
+    /// 主要用于处理要绑定图纸中存在嵌套参照被卸载的情况</param>
+    /// <param name="xrefSymTabTypeNum">累计要绑定的符号表数量，默认为LayerTable=0"无敌绑定"项.最小为0，最大为4
+    /// 具体【0为"图层表",1为"文字样式表",2为"标注样式表",3为"线型表",4为"注册应用程序表"】</param>
+    /// <returns>无返回值,以ref方式传出被卸载嵌套参照名称及句柄的字典</returns>
+    public static void XBindXrefs(Database db, ref Dictionary<Handle, string> isNestedNodeNameDic, XrefSymTabTypeNum xrefSymTabTypeNum = XrefSymTabTypeNum.LayerTable)
+    {
+        var workingDb = HostApplicationServices.WorkingDatabase;//数据库转换
+        HostApplicationServices.WorkingDatabase = db;//数据库转换
+        
+        db.ResolveXrefs(false, false);//解析数据库
+
+        Dictionary<Handle, string> isNestedNodeName = isNestedNodeNameDic;//要处理的嵌套参照的数据字典
+
+        var bindXrefsIds = new ObjectIdCollection();//声明要BindXrefs的集合
+        var xBindXrefsIds = new ObjectIdCollection();//声明要XBindXrefs的集合
+        var isNestedIds = new ObjectIdCollection();//要处理的嵌套参照ObjectId集合
+
+        using (var tr = db.TransactionManager.StartTransaction())
+        {
+            #region 原块表参照的id集合获取
+            var bt = (BlockTable)tr.GetObject(db.BlockTableId, OpenMode.ForRead);//块表
+            foreach (ObjectId id in bt)
+            {
+                var btr = (BlockTableRecord)tr.GetObject(id, OpenMode.ForRead);
+                if (btr.IsFromExternalReference && btr.IsResolved)
+                    bindXrefsIds.Add(id);
+            }
+            #endregion
+
+            #region 补充是否被嵌套卸载的处理
+            XrefGraph xg = db.GetHostDwgXrefGraph(true);
+            int xrefcount = xg.NumNodes;
+            for (int j = 0; j < xrefcount; j++)
+            {
+                XrefGraphNode xrNode = xg.GetXrefNode(j);
+                if (xrNode.XrefStatus == XrefStatus.Unloaded)//若文件已卸载
+                {
+                    ObjectId deTachId = xrNode.BlockTableRecordId;
+                    BlockTableRecord btr = (BlockTableRecord)tr.GetObject(deTachId, OpenMode.ForRead);
+                    if (btr.IsFromExternalReference)
+                    {
+                        if (!xrNode.IsNested)//若为非嵌套参照
+                        {
+                            db.DetachXref(deTachId);//拆离已经卸载的非嵌套文件
+                        }
+                        else//若为嵌套参照
+                        {
+                            isNestedIds.Add(deTachId);
+                            isNestedNodeName.Add(deTachId.Handle, xrNode.Name);//有嵌套参照，添加关键信息进字典，以传出方法供绑定后删除处理
+                        }
+                    }
+                }
+                if (xrNode.XrefStatus == XrefStatus.Unreferenced)//若文件未参照
+                {
+                    db.DetachXref(xrNode.BlockTableRecordId);//拆离未参照的文件
+                }
+                #region 使用此方法添加的xrNode.BlockTableRecordId，绑定中会随机出现异常（勿用）
+                //if (xrNode.XrefStatus == XrefStatus.Resolved)//若文件已解析
+                //{
+                //    ObjectId bindXrefId = xrNode.BlockTableRecordId;
+                //    BlockTableRecord btr = (BlockTableRecord)tr.GetObject(bindXrefId, OpenMode.ForRead);
+                //    if (btr.IsFromExternalReference)
+                //    {
+                //      xrefIds.Add(bindXrefId);
+                //    }
+                //}
+                #endregion
+            }
+            #endregion
+
+            #region 添加XBindXrefs符号表记录id。根据symbolTableRecordNum值范围0~4动态控制5个符号表记录累加绑定需求
+            int symbolTableRecordNum = 0;
+            switch (xrefSymTabTypeNum)
+            {
+                case XrefSymTabTypeNum.LayerTable:
+                    symbolTableRecordNum = 0;
+                    break;
+                case XrefSymTabTypeNum.TextStyleTable:
+                    symbolTableRecordNum = 1;
+                    break;
+                case XrefSymTabTypeNum.DimStyleTable:
+                    symbolTableRecordNum = 2;
+                    break;
+                case XrefSymTabTypeNum.LinetypeTable:
+                    symbolTableRecordNum = 3;
+                    break;
+                case XrefSymTabTypeNum.RegAppTable:
+                    symbolTableRecordNum = 4;
+                    break;
+            }
+            if (symbolTableRecordNum >= 0)//为0时被本人称为"无敌绑定"项
+            {
+                LayerTable layert = tr.GetObject(db.LayerTableId, OpenMode.ForRead) as LayerTable;//图层表
+                foreach (ObjectId id in layert)
+                {
+                    LayerTableRecord ltr = (LayerTableRecord)tr.GetObject(id, OpenMode.ForRead);
+                    if (ltr.IsResolved)
+                    {
+                        xBindXrefsIds.Add(ltr.ObjectId);
+                    }
+                }
+            }
+            if (symbolTableRecordNum >= 1)
+            {
+                TextStyleTable textstylet = tr.GetObject(db.TextStyleTableId, OpenMode.ForRead) as TextStyleTable;//文字样式表
+                foreach (ObjectId id1 in textstylet)
+                {
+                    TextStyleTableRecord textstyletr = (TextStyleTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+                    if (textstyletr.IsResolved)
+                    {
+                        xBindXrefsIds.Add(textstyletr.ObjectId);
+                    }
+                }
+            }
+            if (symbolTableRecordNum >= 2)
+            {
+                LinetypeTable linetypet = tr.GetObject(db.LinetypeTableId, OpenMode.ForRead) as LinetypeTable;//线型表
+                foreach (ObjectId id1 in linetypet)
+                {
+                    LinetypeTableRecord linetr = (LinetypeTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+                    if (linetr.IsResolved)
+                    {
+                        xBindXrefsIds.Add(linetr.ObjectId);
+                    }
+                }
+            }
+            if (symbolTableRecordNum >= 3)
+            {
+                DimStyleTable dimt = tr.GetObject(db.DimStyleTableId, OpenMode.ForRead) as DimStyleTable;//标注样式表
+                foreach (ObjectId id1 in dimt)
+                {
+                    DimStyleTableRecord dtr = (DimStyleTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+                    if (dtr.IsResolved)
+                    {
+                        xBindXrefsIds.Add(dtr.ObjectId);
+                    }
+                }
+            }
+            if (symbolTableRecordNum >= 4)
+            {
+                RegAppTable regappt = tr.GetObject(db.RegAppTableId, OpenMode.ForRead) as RegAppTable;//注册应用程序表
+                foreach (ObjectId id1 in regappt)
+                {
+                    RegAppTableRecord regapptr = (RegAppTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+                    if (regapptr.IsResolved)
+                    {
+                        xBindXrefsIds.Add(regapptr.ObjectId);
+                    }
+                }
+            }
+            #region 起初测试是将9大符号表记录均加入的，但经实测不行。所以根据截取帮助文件中描述，仅添加了块表外的5表记录id
+            ///xrefSymbolIds可能包含以下符号表记录类型的 ObjectId：
+            ///BlockTableRecord、LayerTableRecord、LinetypeTableRecord、TextStyleTableRecord（如果它不代表形状文件）、RegAppTableRecord和DimStyleTableRecord。
+
+            //ViewportTable viewport = tr.GetObject(db.ViewportTableId, OpenMode.ForRead) as ViewportTable;//视口表
+            //foreach (ObjectId id1 in viewport)
+            //{
+            //    ViewportTableRecord viewportr = (ViewportTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+            //    if (viewportr.IsResolved)
+            //    {
+            //      xrefIds1.Add(viewportr.ObjectId);
+            //    }
+            //}
+            //ViewTable viewt = tr.GetObject(db.ViewTableId, OpenMode.ForRead) as ViewTable;// 视图表
+            //foreach (ObjectId id1 in viewt)
+            //{
+            //    ViewTableRecord viewtr = (ViewTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+            //    if (viewtr.IsResolved)
+            //    {
+            //      xrefIds1.Add(viewtr.ObjectId);
+            //    }
+            //}
+            //UcsTable ucst = tr.GetObject(db.UcsTableId, OpenMode.ForRead) as UcsTable;// 用户坐标系表
+            //foreach (ObjectId id1 in ucst)
+            //{
+            //    UcsTableRecord ucstr = (UcsTableRecord)tr.GetObject(id1, OpenMode.ForRead);
+            //    if (ucstr.IsResolved)
+            //    {
+            //      xrefIds1.Add(ucstr.ObjectId);
+            //    }
+            //}
+            #endregion
+            #endregion
+        }
+
+        if (isNestedIds.Count > 0)//若有嵌套参照被卸载，重载
+        {
+            db.ReloadXrefs(isNestedIds);
+        }
+
+        #region 此处即为二者结合使用，且顺序非常重要。若交换秩序，则会绑定无效，切勿交换
+        db.XBindXrefs(xBindXrefsIds, true);//建议为true
+        db.BindXrefs(bindXrefsIds, true);//建议为true
+        #endregion
+
+        isNestedNodeNameDic = isNestedNodeName;
+        HostApplicationServices.WorkingDatabase = workingDb;
+    }
+    /// <summary>
+    /// 清理符号7表(块表,标注样式表,图层表,线型表,文字样式表,视口样式表,注册应用表)
+    ///注:视图样式表和坐标系表不能这样清理,有异常
+    /// </summary>
+    /// <param name="db">数据库</param>
+    /// <returns>无返回值</returns>
+    public static void Purge(Database db)
+    {
+        ObjectIdCollection ids;
+        ObjectIdCollection ids1;
+        ObjectIdCollection ids2;
+        ObjectIdCollection ids3;
+        ObjectIdCollection ids4;
+        ObjectIdCollection ids5;
+        //ObjectIdCollection ids6;
+        //ObjectIdCollection ids7;
+        ObjectIdCollection ids8;
+        using (Transaction tr = db.TransactionManager.StartTransaction())
+        {
+            //块表
+            BlockTable blockt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;
+            //标注样式表1
+            DimStyleTable dimt = tr.GetObject(db.DimStyleTableId, OpenMode.ForRead) as DimStyleTable;
+            //图层表2
+            LayerTable layert = tr.GetObject(db.LayerTableId, OpenMode.ForRead) as LayerTable;
+            //线型表3
+            LinetypeTable linetypet = tr.GetObject(db.LinetypeTableId, OpenMode.ForRead) as LinetypeTable;
+            //文字样式4
+            TextStyleTable textstylet = tr.GetObject(db.TextStyleTableId, OpenMode.ForRead) as TextStyleTable;
+            //视口样式表5
+            ViewportTable viewport = tr.GetObject(db.ViewportTableId, OpenMode.ForRead) as ViewportTable;
+            //注册应用表8
+            RegAppTable regappt = tr.GetObject(db.RegAppTableId, OpenMode.ForRead) as RegAppTable;
+
+            #region 开始清理
+            do
+            {
+                ids = new ObjectIdCollection(blockt.Cast<ObjectId>().ToArray());
+                db.Purge(ids);
+                if (ids != null)
+                {
+                    foreach (ObjectId id in ids)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+                ids1 = new ObjectIdCollection(dimt.Cast<ObjectId>().ToArray());
+                db.Purge(ids1);
+                if (ids1 != null)
+                {
+                    foreach (ObjectId id in ids1)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+                ids2 = new ObjectIdCollection(layert.Cast<ObjectId>().ToArray());
+                db.Purge(ids2);
+                if (ids2 != null)
+                {
+                    foreach (ObjectId id in ids2)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+                ids3 = new ObjectIdCollection(linetypet.Cast<ObjectId>().ToArray());
+                db.Purge(ids3);
+                if (ids3 != null)
+                {
+                    foreach (ObjectId id in ids3)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+                ids4 = new ObjectIdCollection(textstylet.Cast<ObjectId>().ToArray());
+                db.Purge(ids4);
+                if (ids4 != null)
+                {
+                    foreach (ObjectId id in ids4)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+                ids5 = new ObjectIdCollection(viewport.Cast<ObjectId>().ToArray());
+                db.Purge(ids5);
+                if (ids5 != null)
+                {
+                    foreach (ObjectId id in ids5)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+                #region 经测试视图样式表和坐标系表不能这样清理,不然有异常
+                ////视图样式表6
+                //ViewTable viewt = tr.GetObject(db.ViewTableId, OpenMode.ForRead) as ViewTable;
+                //ids6 = new ObjectIdCollection(viewt.Cast<ObjectId>().ToArray());
+                //db.Purge(ids6);
+                //foreach (ObjectId id in ids6)
+                //{
+                //    ViewTableRecord btr6 = (ViewTableRecord)tr.GetObject(id, OpenMode.ForWrite);
+                //    btr6.Erase();
+                //}
+                ////坐标系表7
+                //UcsTable ucst = tr.GetObject(db.UcsTableId, OpenMode.ForRead) as UcsTable;
+                //ids7 = new ObjectIdCollection(ucst.Cast<ObjectId>().ToArray());
+                //db.Purge(ids7);
+                //foreach (ObjectId id in ids7)
+                //{
+                //    UcsTableRecord btr7 = (UcsTableRecord)tr.GetObject(id, OpenMode.ForWrite);
+                //    btr7.Erase();
+                //}
+                #endregion
+                ids8 = new ObjectIdCollection(regappt.Cast<ObjectId>().ToArray());
+                db.Purge(ids8);
+                if (ids8 != null)
+                {
+                    foreach (ObjectId id in ids8)
+                    {
+                        tr.GetObject(id, OpenMode.ForWrite).Erase();
+                    }
+                }
+            } while (ids.Count > 0 || ids1.Count > 0 || ids2.Count > 0 || ids3.Count > 0 || ids4.Count > 0 || ids5.Count > 0 || ids8.Count > 0);
+            #endregion
+
+            tr.Commit();//提交事务
+        }
+    }
+} 
\ No newline at end of file