AutoCad 二次开发 .net 之层表的增加 删除 修改图层颜色 遍历 设置当前层

AutoCad 二次开发 .net 之层表的增加 删除 修改图层颜色 遍历 设置当前层
我理解的图层的作用大概是把相同作用的功能聚集在一起，以便好选择。比如，把一副图块中的所有标注定义为一个图层，把编号定义为一个图层，把相同的块参照定义为一个图层。图层表的操作和块表的操作类似。

在这里我就分享一下自己从书《AUTOCAD VBA&VB.NET开发基础与实例教程(C#版) 第2版》学习到的关于图层的一些操作的代码，我觉得主要是图层的删除需要注意一下。

 

使用的成员变量：

Document Doc = Application.DocumentManager.MdiActiveDocument;
Editor Ed = Application.DocumentManager.MdiActiveDocument.Editor;
Database Db = Application.DocumentManager.MdiActiveDocument.Database;

一、图层的删除 代码：

        /// <summary>
        /// 图层0和图层Defpoints不能被删除，当前图层不能被删除，图层上有块参照，实体时不能被删除
        /// 删除前需刷新，使用LayerTableRecord.GenerateUsageData();
        /// </summary>
        public bool DeleteLayer(Database db, string layerName)
        {

            using (var trans = db.TransactionManager.StartTransaction())
            {

                var lyTbl = trans.GetObject(db.LayerTableId, OpenMode.ForWrite) as LayerTable;

                if (!lyTbl.Has(layerName)) return false;

                if (layerName == "0" || layerName == "Defpoints") return false;

                ObjectId oId = lyTbl[layerName];

                if (oId == db.Clayer) return false;

                var lyTblRec = trans.GetObject(lyTbl[layerName], OpenMode.ForRead) as LayerTableRecord;

                lyTbl.GenerateUsageData();

                if (lyTblRec.IsUsed) return false;

                lyTblRec.UpgradeOpen();

                lyTblRec.Erase(true);

                trans.Commit();

                return true;
            }
        }

二、图层的增加：

public ObjectId AddLayer(Database db, string layerName)
        {
            ObjectId oId = ObjectId.Null;

            using (var trans = db.TransactionManager.StartTransaction())
            {
                var lyerTbl = db.LayerTableId.GetObject(OpenMode.ForWrite) as LayerTable;

                if (lyerTbl.Has(layerName))
                {
                    trans.Commit();
                    return lyerTbl[layerName];
                }
                var lyerTblRec = new LayerTableRecord();
                lyerTblRec.Name = layerName;

                lyerTbl.Add(lyerTblRec);
                trans.AddNewlyCreatedDBObject(lyerTblRec, true);

                lyerTbl.DowngradeOpen();

                trans.Commit();

                return lyerTbl[layerName];
            }
        }

三、修改图层颜色：

 public bool SetLayerColor(Database db, string layerName, short colorIndexs)
        {

            using (var trans = db.TransactionManager.StartTransaction())
            {

                var lyTbl = db.LayerTableId.GetObject(OpenMode.ForRead) as LayerTable;

                if (lyTbl.Has(layerName))
                {
                    var lyTblRec = trans.GetObject(lyTbl[layerName], OpenMode.ForWrite) as LayerTableRecord;

                    if (colorIndexs < 0 || colorIndexs > 255)
                    {
                        colorIndexs = 1;
                    }
                    lyTblRec.Color = Color.FromColorIndex(ColorMethod.ByAci, colorIndexs);

                    lyTblRec.DowngradeOpen();

                    trans.Commit();
                    return true;

                }
                else
                {
                    return false;
                }
            }
        }

四、遍历图层：

public List<LayerTableRecord> GetAllLayer(Database db)
        {
            List<LayerTableRecord> listLyTblRec = new List<LayerTableRecord>();

            using (var trans = db.TransactionManager.StartTransaction())
            {

                var lyTbl = trans.GetObject(db.LayerTableId, OpenMode.ForRead) as LayerTable;

                foreach (ObjectId oId in lyTbl)
                {

                    var lyTblRec = trans.GetObject(oId, OpenMode.ForRead) as LayerTableRecord;

                    listLyTblRec.Add(lyTblRec);

                }

                return listLyTblRec;
            }
        }

五、设置当前图层：

Databse.Clayer表示当前图层
  public bool SetCurrentLayer(Database db, string layerName)
        {

            using (var trans = db.TransactionManager.StartTransaction())
            {

                var lyTbl = trans.GetObject(db.LayerTableId, OpenMode.ForRead) as LayerTable;

                if (!lyTbl.Has(layerName)) return false;

                //var lyTblRec = trans.GetObject(lyTbl[layerName], OpenMode.ForRead) as LayerTableRecord;

                if (db.Clayer != lyTbl[layerName])
                {
                    db.Clayer = lyTbl[layerName];
                }
                return true;
            }

        }

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