CAD开发 选择实体并拖动

using System;
using System.Collections.Generic;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;

namespace DragExample
{
    public class DragCommands
    {
        [CommandMethod("DragSelection")]
        public void DragSelection()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;
            Editor ed = doc.Editor;

            // 提示用户选择实体
            PromptSelectionOptions pso = new PromptSelectionOptions();
            pso.MessageForAdding = "选择要拖拽的实体: ";
            PromptSelectionResult psr = ed.GetSelection(pso);
            if (psr.Status != PromptStatus.OK)
                return;

            SelectionSet ss = psr.Value;
            if (ss.Count == 0)
            {
                ed.WriteMessage("\n未选择任何实体。");
                return;
            }

            // 获取基点
            PromptPointOptions ppo = new PromptPointOptions("\n指定基点: ");
            PromptPointResult pprBase = ed.GetPoint(ppo);
            if (pprBase.Status != PromptStatus.OK)
                return;

            Point3d basePoint = pprBase.Value;

            // 定义拖拽回调，用于计算变换矩阵
            DragCallback dragCallback = (Point3d pt, ref Matrix3d mat) =>
            {
                if (basePoint.Equals(pt))
                    return SamplerStatus.NoChange;
                mat = Matrix3d.Displacement(basePoint.GetVectorTo(pt));
                return SamplerStatus.OK;
            };

            // 开始拖拽操作
            PromptPointResult ppr = ed.Drag(ss, "\n指定第二点: ", dragCallback);
            if (ppr.Status == PromptStatus.OK)
            {
                // 获取最终点并应用变换
                Point3d secondPoint = ppr.Value;
                Matrix3d finalMat = Matrix3d.Displacement(basePoint.GetVectorTo(secondPoint));

                using (Transaction tr = db.TransactionManager.StartTransaction())
                {
                    ObjectId[] ids = ss.GetObjectIds();
                    foreach (ObjectId id in ids)
                    {
                        Entity ent = (Entity)tr.GetObject(id, OpenMode.ForWrite);
                        ent.TransformBy(finalMat);
                    }
                    tr.Commit();
                }

                ed.WriteMessage($"\n成功拖拽了 {ss.Count} 个实体。");
            }
            else
            {
                ed.WriteMessage("\n拖拽操作已取消。");
            }
        }
    }
}