跨图形实体拷贝

当需要将外部DWG图纸中的某些内容拷贝到当前图形时，可以在后台加载DWG，进而从后台数据库中拷贝对象。
本文提供一个示例。

将外部图纸的所有实体拷贝到当前图形

可以通过IdMapping拿到原实体和拷贝实体的ObjectId，从而进行后续操作。

public static bool CopyAllEntity(this Document destinationDoc, string sourceDwgPath, out List<ObjectId> newIds, bool isReplace = false)
{
    // 返回拷贝实体的Id
    newIds = new List<ObjectId>();    
    Database curdb = destinationDoc.Database;
    using (Database db = new Database(false, true))
    {
        db.ReadDwgFile(sourceDwgPath, FileShare.ReadWrite, true, null);
        Autodesk.AutoCAD.DatabaseServices.TransactionManager tm = db.TransactionManager;
        ObjectIdCollection blockIds = new ObjectIdCollection();
        using (Transaction tran = tm.StartTransaction())
        {
            BlockTable bt = (BlockTable)tm.GetObject(db.BlockTableId, OpenMode.ForRead, false);
            BlockTableRecord btr = (BlockTableRecord)tm.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForRead, false);
            foreach (ObjectId btrId in btr)
                blockIds.Add(btrId);
            tran.Commit();
        }

        IdMapping mapping = new IdMapping();
        using (DocumentLock docLock = destinationDoc.LockDocument())
        {
            using (Transaction trans = destinationDoc.TransactionManager.StartTransaction())
            {
                BlockTable bt2 = (BlockTable)trans.GetObject(curdb.BlockTableId, OpenMode.ForWrite, false);
                DuplicateRecordCloning cloning = isReplace ? DuplicateRecordCloning.Replace : DuplicateRecordCloning.Ignore;
                db.WblockCloneObjects(blockIds, bt2[BlockTableRecord.ModelSpace], mapping, cloning, false);
                trans.Commit();
            }
        }
        // 实体Id映射关系存储在IdMapping中
        foreach (IdPair ids in mapping)
            newIds.Add(ids.Value);
    }
    return true;
}