using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Diagnostics;using Autodesk.AutoCAD.Runtime;using Autodesk.AutoCAD.DatabaseServices;using Autodesk.AutoCAD.ApplicationServices;using Autodesk.AutoCAD.EditorInput;/// <summary>/// 选择集比较/// </summary>/// [assembly: CommandClass(typeof(TipsAndTricks.Class1))]namespace TipsAndTricks{    public class Class1    {        [CommandMethod("Test")]        public void test()        {            DoFilter(FilterByEdSelectionFilter);            DoFilter(FilterByLinq);            DoFilter(FilterByForeach);        }        private static void DoFilter(Action action)        {            var ed = Application.DocumentManager.MdiActiveDocument.Editor;            var sw = Stopwatch.StartNew();            action();            sw.Stop();            ed.WriteMessage($"{sw.Elapsed.TotalMilliseconds}\n");        }                public void FilterByEdSelectionFilter()        {            var ed = Application.DocumentManager.MdiActiveDocument.Editor;            TypedValue[] circType = new TypedValue[1];            circType.SetValue(new TypedValue((int)DxfCode.Start, "CIRCLE"), 0);             SelectionFilter filtCirc = new SelectionFilter(circType);            PromptSelectionResult resPrompt;            resPrompt = ed.SelectAll(filtCirc);            if (resPrompt.Status == PromptStatus.OK)            {                SelectionSet circSelSet = resPrompt.Value;                ed.WriteMessage($"ed count: {circSelSet.Count.ToString()}\n");//vs2015 新语法 可以正常编译.net 4.0的项目            }        }             public void FilterByLinq()        {            var db = HostApplicationServices.WorkingDatabase;            var ed = Application.DocumentManager.MdiActiveDocument.Editor;            using (var tr = db.TransactionManager.StartTransaction())            {                var bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;                var mspace = tr.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForRead, false) as BlockTableRecord;                               var circles = mspace.Cast<ObjectId>()                    .Where(id => id.ObjectClass.DxfName.Equals("CIRCLE")); //过滤条件很关键,对性能影响很大                ed.WriteMessage($"linq count: {circles.Count().ToString()}\n");            }        }                public void FilterByForeach()        {            var db = HostApplicationServices.WorkingDatabase;            Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;            using (var tr = db.TransactionManager.StartTransaction())            {                var bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;                var mspace = tr.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForRead, false) as BlockTableRecord;                var circles = new List<ObjectId>();                foreach (ObjectId id in mspace)                {                    var dbObj = tr.GetObject(id, OpenMode.ForRead) as Circle;                    if (dbObj != null)                    {                        circles.Add(dbObj.Id);                    }                }                ed.WriteMessage($"Foreach count: {circles.Count.ToString()}\n");
            }        }    }}