AutoCAD .net 开发 SelectionFilter Foreach Linq 性能比较

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");
            }
        }
    }
}

目前看来 linq 效率挺高的,以后开发可以放心用linq做二次开发了.

------------------------

4m的dwg 图纸 测试结果:　　

ed count: 877
96.0967
linq count: 877
67.8107
Foreach count: 877
156.6604