Cad.Net 直线合并（最后的到的都是直线的端点合并后的两个端点，k和b列表）

using System;
using System.Collections.Generic;
using System.Linq;
using ZwSoft.ZwCAD.ApplicationServices;
using ZwSoft.ZwCAD.DatabaseServices;
using ZwSoft.ZwCAD.EditorInput;
using ZwSoft.ZwCAD.Geometry;
using ZwSoft.ZwCAD.Runtime;
using ZWApp = ZwSoft.ZwCAD.ApplicationServices.Application;
//最后结果为{{k，b，p1，p2}，{k，b，p1，p2}}
namespace CADToExcel
{
    public static class Class1
    {
        public static Document doc = ZWApp.DocumentManager.MdiActiveDocument;
        public static Database db = HostApplicationServices.WorkingDatabase;
        public static Editor ed = doc.Editor;
        [CommandMethod("CTE", CommandFlags.Session | CommandFlags.UsePickSet)]
        public static void CTE()
        {
            List<Entity> linelst = new List<Entity>();
            List<LInfo> linfo = new List<LInfo>();
            using (DocumentLock dloc = doc.LockDocument())
            {
                TypedValue[] value = new TypedValue[] { new TypedValue((int)DxfCode.Start, "LWPOLYLINE,LINE") };
                SelectionFilter filter = new SelectionFilter(value);
                PromptSelectionResult psr = ed.GetSelection(filter);
                ObjectId[] ids = psr.Value.GetObjectIds();
                using (Transaction tr = db.TransactionManager.StartTransaction())
                {
                    //打开块表记录
                    BlockTableRecord btr = tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;
                    linelst = ids.Cast<ObjectId>().Select(id => (Entity)id.GetObject(OpenMode.ForWrite)).ToList();
                }
                foreach (Entity lent in linelst)
                {
                    if ("Line".Equals(lent.GetType().Name, StringComparison.CurrentCultureIgnoreCase))
                    {
                        Line l = (Line)lent;
                        linfo.Add(Line_Data(l.StartPoint, l.EndPoint));
                    }
                    else
                    {
                        Polyline pl = (Polyline)lent;
                        int ptn = pl.NumberOfVertices - 1;
                        for (int i = 0; i < ptn; i++)
                        {
                            linfo.Add(Line_Data(pl.GetPoint3dAt(i), pl.GetPoint3dAt(i + 1)));
                        }
                        if (pl.Closed) linfo.Add(Line_Data(pl.GetPoint3dAt(ptn), pl.GetPoint3dAt(0)));
                    }
                }
                //rowLine = rowLine.OrderByDescending(linept => linept.Value).ToList();
                //colLine = colLine.OrderBy(linept => linept.Value).ToList();
                linfo.Sort((e1, e2) =>
                {
                    if (e1.K.EqOfDis(e2.K))
                    {
                        if (e1.B.EqOfDis(e2.B))
                        {
                            if (e1.P1.X.EqOfDis(e2.P2.X)) return e1.P1.Y.CompareTo(e1.P2.Y);
                            else return e1.P1.X.CompareTo(e1.P2.X);
                        }
                        else return e1.B.CompareTo(e2.B);
                    }
                    else return e1.K.CompareTo(e2.K);
                });
                linfo = linfo.HB_Line();
            }
        }
        #region MyRegion 合并使用函数
        public struct LInfo
        {
            public LInfo(double value, double k, double b, Point3d p1, Point3d p2)
            {
                Value = value;
                K = k;
                B = b;
                P1 = p1;
                P2 = p2;
            }
            public double Value { set; get; }
            public double K { set; get; }
            public double B { set; get; }
            public Point3d P1 { set; get; }
            public Point3d P2 { set; get; }
        }
        //容差比较两个数
        public static bool EqOfDis(this double value1, double value2, double dis = 1e-06) => Math.Abs(value1 - value2) <= dis;
        //容差比较两个点的距离
        public static bool EqOfDis(this Point3d pt1, Point3d pt2, double dis = 1e-06) => Math.Abs(pt1.X - pt2.X) < dis && Math.Abs(pt1.Y - pt2.Y) < dis && Math.Abs(pt1.Z - pt2.Z) < dis;
        public static LInfo Line_Data(Point3d pt1, Point3d pt2)
        {
            double k, b;
            if (pt1.X.EqOfDis(pt2.X))
            {
                k = double.NaN;
                b = pt1.X;
            }
            else
            {
                k = (pt2.Y - pt1.Y) / (pt2.X - pt1.X);
                b = pt1.Y - (pt1.X * k);
            }
            return pt1.X.EqOfDis(pt2.X)
                ? pt1.Y > pt2.Y ? new LInfo(k, b, pt2, pt1) : new LInfo(k, b, pt1, pt2)
                : pt1.X > pt2.X ? new LInfo(k, b, pt2, pt1) : new LInfo(k, b, pt1, pt2);
        }
        public static List<LInfo> HB_Line(this List<LInfo> linelst)
        {
            List<LInfo> newlst = new List<LInfo>();
            int count = linelst.Count, i = 0, index = 0;
            double k, b;
            Point3d p1, p2, p3, p4;
            while (linelst.Count > 0)
            {
                index++;
                LInfo lia = linelst[0];
                linelst.Remove(lia);
                bool mark = true;
                k = lia.K;
                b = lia.B;
                p1 = lia.P1;
                p2 = lia.P2;
                while (mark && linelst.Count > 0)
                {
                    LInfo lib = linelst[0];
                    if (k.EqOfDis(lib.K) && b.EqOfDis(lib.B))
                    {
                        p3 = lib.P1;
                        p4 = lib.P2;
                        List<Point3d> plst = new List<Point3d> { p1, p2, p3, p4 };
                        plst.Sort((pa, pb) =>
                        {
                            return pa.X.EqOfDis(pb.X) ? pa.Y.CompareTo(pb.Y) : pa.X.CompareTo(pb.X);
                        });
                        p4 = plst[1];
                        if (p1.EqOfDis(p4) || p3.EqOfDis(p4))
                        {
                            p1 = plst.First();
                            p2 = plst.Last();
                            linelst.Remove(lib);
                            index++;
                            i++;
                        }
                        else mark = false;
                    }
                    else mark = false;
                }
                newlst.Add(new LInfo(lia.Value, lia.K, lia.B, p1, p2));
            }
            return newlst;
        }
        #endregion
    }
}