C# AutoCAD2010选择dwg中的一个块，获取其位置后，再在电脑本地选择一个外部块，在该位置去替换它 ，完整代码

以下是一个示例代码，实现了在 AutoCAD 中选择一个块，并在本地选择一个块文件，将其替换到选择的块的位置：

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;
using System.IO;
using System.Windows.Forms;

namespace ReplaceBlock
{
    public class Class1
    {
        [CommandMethod("ReplaceBlock")]
        public void ReplaceBlock()
        {
            // 获取当前文档和数据库
            Document acDoc = Application.DocumentManager.MdiActiveDocument;
            Database acCurDb = acDoc.Database;

            // 提示用户选择要替换的块
            PromptEntityOptions peo = new PromptEntityOptions("\n选择要替换的块：");
            peo.SetRejectMessage("\n请选择块实体。");
            peo.AddAllowedClass(typeof(BlockReference), true);
            PromptEntityResult per = acDoc.Editor.GetEntity(peo);

            if (per.Status != PromptStatus.OK)
            {
                return;
            }

            // 获取选中的块的位置和属性
            using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
            {
                BlockReference br = acTrans.GetObject(per.ObjectId, OpenMode.ForRead) as BlockReference;
                if (br == null)
                {
                    return;
                }

                Point3d position = br.Position;
                ObjectId blockId = br.BlockTableRecord;

                BlockTableRecord btr = acTrans.GetObject(blockId, OpenMode.ForRead) as BlockTableRecord;
                if (btr == null)
                {
                    return;
                }

                // 将块分解为实体，并获取属性信息
                BlockTableRecord modelSpace = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;
                ObjectIdCollection ids = new ObjectIdCollection();
                foreach (ObjectId objId in btr)
                {
                    ids.Add(objId);
                }
                DBObjectCollection objs = new DBObjectCollection();
                acCurDb.Explode(ids, objs);
                AttributeCollection attrs = null;
                foreach (DBObject obj in objs)
                {
                    Entity ent = obj as Entity;
                    if (ent != null)
                    {
                        modelSpace.AppendEntity(ent);
                        acTrans.AddNewlyCreatedDBObject(ent, true);
                        if (ent is BlockReference)
                        {
                            BlockReference blkRef = ent as BlockReference;
                            if (blkRef.BlockTableRecord == blockId)
                            {
                                attrs = blkRef.AttributeCollection;
                            }
                        }
                    }
                }

                // 提示用户选择要替换的块文件
                OpenFileDialog ofd = new OpenFileDialog();
                ofd.Filter = "DWG文件|*.dwg";
                ofd.Multiselect = false;
                if (ofd.ShowDialog() != DialogResult.OK)
                {
                    return;
                }

                // 在选择的块的位置创建新的块，并设置属性
                BlockTable bt = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead) as BlockTable;
                if (bt == null)
                {
                    return;
                }
                BlockTableRecord btrNew = new BlockTableRecord();
                btrNew.Name = "*U";
                bt.UpgradeOpen();
                bt.Add(btrNew);
                acTrans.AddNewlyCreatedDBObject(btrNew, true);
                BlockReference brNew = new BlockReference(position, btrNew.ObjectId);
                modelSpace.AppendEntity(brNew);
                acTrans.AddNewlyCreatedDBObject(brNew, true);
                if (attrs != null)
                {
                    foreach (ObjectId attrId in attrs)
                    {
                        AttributeReference attr = acTrans.GetObject(attrId, OpenMode.ForRead) as AttributeReference;
                        if (attr != null)
                        {
                            AttributeReference attrNew = attr.Clone() as AttributeReference;
                            if (attrNew != null)
                            {
                                brNew.AttributeCollection.AppendAttribute(attrNew);
                                acTrans.AddNewlyCreatedDBObject(attrNew, true);
                            }
                        }
                    }
                }

                // 将选择的块插入到新创建的块的位置
                Database acDbExt = new Database(false, true);
                acDbExt.ReadDwgFile(ofd.FileName, FileOpenMode.OpenForReadAndAllShare, false, "");
                using (Transaction acTransExt = acDbExt.TransactionManager.StartTransaction())
                {
                    BlockTable btExt = acTransExt.GetObject(acDbExt.BlockTableId, OpenMode.ForRead) as BlockTable;
                    if (btExt == null)
                    {
                        return;
                    }
                    BlockTableRecord btrExt = acTransExt.GetObject(btExt[BlockTableRecord.ModelSpace], OpenMode.ForRead) as BlockTableRecord;
                    if (btrExt == null)
                    {
                        return;
                    }
                    foreach (ObjectId objId in btrExt)
                    {
                        Entity entExt = acTransExt.GetObject(objId, OpenMode.ForRead) as Entity;
                        if (entExt != null && entExt is BlockReference)
                        {
                            BlockReference blkRefExt = entExt as BlockReference;
                            if (blkRefExt.Name == Path.GetFileNameWithoutExtension(ofd.FileName))
                            {
                                BlockReference blkRefExtNew = blkRefExt.Clone() as BlockReference;
                                if (blkRefExtNew != null)
                                {
                                    blkRefExtNew.Position = position;
                                    brNew.SetBlockReferenceId(blkRefExtNew.BlockTableRecord, true);
                                    foreach (ObjectId attrId in blkRefExt.AttributeCollection)
                                    {
                                        AttributeReference attrExt = acTransExt.GetObject(attrId, OpenMode.ForRead) as AttributeReference;
                                        if (attrExt != null)
                                        {
                                            AttributeReference attrNew = attrExt.Clone() as AttributeReference;
                                            if (attrNew != null)
                                            {
                                                blkRefExtNew.AttributeCollection.AppendAttribute(attrNew);
                                                acTrans.AddNewlyCreatedDBObject(attrNew, true);
                                            }
                                        }
                                    }
                                    break;
                                }
                            }
                        }
                    }
                    acTransExt.Commit();
                }

                // 删除原来的块
                br.Erase();

                // 保存修改后的图形
                acTrans.Commit();
            }
        }
    }
}

请注意，此示例代码仅供参考，实际使用时需要根据具体情况进行修改和调整。同时，为了使代码更易于理解和维护，建议将其分解为多个方法或类。