C# AutoCAD2010 dwg文件中选中块，在该块的位置上选择外部块替换，其余位置的块不变的完整代码

以下是使用C#编写的AutoCAD应用程序，用于选择块并在其位置上替换为外部块，同时保留其他位置的块不变。请注意，该代码仅供参考。

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;

namespace BlockReplace
{
    public class BlockReplaceCommands
    {
        [CommandMethod("BR")]
        public void BlockReplace()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;
            Editor ed = doc.Editor;

            // 选择要替换的块
            PromptSelectionResult selRes = ed.GetSelection();
            if (selRes.Status != PromptStatus.OK)
                return;

            SelectionSet selSet = selRes.Value;
            if (selSet == null || selSet.Count == 0)
                return;

            // 获取要替换的块定义
            TypedValue[] filterList = new TypedValue[]
            {
                new TypedValue((int)DxfCode.Start, "BLOCK"),
                new TypedValue((int)DxfCode.BlockName, selSet[0].ObjectId.Handle.Value)
            };
            SelectionFilter filter = new SelectionFilter(filterList);
            ObjectId blkDefId = ObjectId.Null;
            using (Transaction tr = db.TransactionManager.StartTransaction())
            {
                BlockTable bt = (BlockTable)tr.GetObject(db.BlockTableId, OpenMode.ForRead);
                BlockTableRecord btr = (BlockTableRecord)tr.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite);
                foreach (ObjectId id in selSet.GetObjectIds())
                {
                    BlockReference blkRef = (BlockReference)tr.GetObject(id, OpenMode.ForWrite);
                    Point3d pos = blkRef.Position;
                    blkRef.Erase();

                    // 插入新块
                    BlockTableRecord newBtr = new BlockTableRecord();
                    newBtr.Name = "NEW_BLOCK_NAME";
                    bt.UpgradeOpen();
                    ObjectId newBlkDefId = bt.Add(newBtr);
                    tr.AddNewlyCreatedDBObject(newBtr, true);
                    BlockReference newBlkRef = new BlockReference(pos, newBlkDefId);
                    btr.AppendEntity(newBlkRef);
                    tr.AddNewlyCreatedDBObject(newBlkRef, true);

                    // 复制属性
                    foreach (ObjectId attId in blkRef.AttributeCollection)
                    {
                        AttributeReference attRef = (AttributeReference)tr.GetObject(attId, OpenMode.ForRead);
                        AttributeReference newAttRef = new AttributeReference();
                        newAttRef.SetAttributeFromBlock(attRef, newBlkRef.BlockTransform);
                        newBlkRef.AttributeCollection.AppendAttribute(newAttRef);
                        tr.AddNewlyCreatedDBObject(newAttRef, true);
                    }

                    // 删除旧块定义
                    if (blkDefId.IsNull)
                    {
                        BlockTableRecord oldBtr = (BlockTableRecord)tr.GetObject(newBlkRef.BlockTableRecord, OpenMode.ForWrite);
                        blkDefId = oldBtr.ObjectId;
                        oldBtr.Name = "OLD_BLOCK_NAME";
                    }
                }
                tr.Commit();
            }

            // 删除旧块
            ed.Command("_.-PURGE", "B", "OLD_BLOCK_NAME", "N");
        }
    }
}

请注意替换代码中的“NEW_BLOCK_NAME”和“OLD_BLOCK_NAME”为实际的块名称。此外，您还需要将编译后的应用程序加载到AutoCAD中，以便在命令行中调用该命令。