[求助]关于搜索最近节点！

single-yu

我想为下图的每个Point，求出一个线段上的最近节点！

我的思路是：用Point来遍历每个多线段实体的节点，然后比较距离，把最小的节点提取出来！

但是这样对于实体比较多的情况，非常的慢，估计我的方法不对，请高手给我个思路，谢谢了！

 

如图：

雪山飞狐_lzh

看不见图。。。

把代码也贴上吧？

single-yu

代码在单位呢，有时间贴上！

single-yu

d:\4.gif


代码如下：

3. <CommandMethod("GetClosePt")> Public Sub GetClosedPoint()
4.         Dim ClosedPt As New List(Of Point2d) '保存最近点
5.         Dim db As Database = HostApplicationServices.WorkingDatabase
6.         '获取数据库
7.         Dim ed As Editor = Application.DocumentManager.MdiActiveDocument.Editor
8.         '获取editor对象
9.         Dim values As TypedValue() = {New TypedValue(DxfCode.Operator, "<or"), New TypedValue(DxfCode.Start, "Point"), _
10.                               New TypedValue(DxfCode.Start, "LWPOLYLINE"), New TypedValue(DxfCode.Operator, "or>")}
11.         Dim filter As New SelectionFilter(values)
12.         Dim entOpt As New PromptSelectionOptions
13.         entOpt.MessageForAdding = "请选择要处理的实体"
14.         Dim entRes As PromptSelectionResult = ed.GetSelection(entOpt, filter)
15.         If entRes.Status = PromptStatus.OK Then
16.             Dim sSet As SelectionSet = entRes.Value
17.             Dim pts As New List(Of DBPoint)
18.             Dim plines As New List(Of Polyline)
19.             Using trans As Transaction = db.TransactionManager.StartTransaction()
20.                 Dim bt As BlockTable = trans.GetObject(db.BlockTableId, OpenMode.ForRead)
21.                 Dim btr As BlockTableRecord = trans.GetObject(bt.Item(BlockTableRecord.ModelSpace), OpenMode.ForWrite)
22.                 For Each id As ObjectId In sSet.GetObjectIds
23.                     Dim ent As Entity = trans.GetObject(id, OpenMode.ForRead)
24.                     If TypeOf (ent) Is DBPoint Then
25.                         pts.Add(ent)
26.                     Else
27.                         plines.Add(ent)
28.                     End If
29.                 Next
30.                 For Each pt As DBPoint In pts
31.                     Dim ptPosition As Point2d = New Point2d(pt.Position.X, pt.Position.Y)
32.                     Dim Cdist As Double = 1000 '给一个相当大的值作为比较值
33.                     Dim Cpt As New Point2d
34.                     For Each pline As Polyline In plines
35.                         For i As Integer = 0 To pline.NumberOfVertices - 1
36.                             Dim dist As Double = ptPosition.GetDistanceTo(pline.GetPoint2dAt(i))
37.                             If dist < Cdist Then
38.                                 Cdist = dist
39.                                 Cpt = pline.GetPoint2dAt(i)
40.                             End If
41.                         Next
42.                     Next
43.                     ClosedPt.Add(Cpt)
44.                 Next
45.                 For Each pt1 As Point2d In ClosedPt
46.                     Dim circle As New Circle(New Point3d(pt1(0), pt1(1), 0), Vector3d.ZAxis, 8)
47.                     btr.AppendEntity(circle)
48.                     trans.AddNewlyCreatedDBObject(circle, True)
49.                 Next
50.                 trans.Commit()
51.             End Using
52.         End If
53.     End Sub

<CommandMethod("GetClosePt")> Public Sub GetClosedPoint()         Dim ClosedPt As New List(Of Point2d) '保存最近点         Dim db As Database = HostApplicationServices.WorkingDatabase         '获取数据库         Dim ed As Editor = Application.DocumentManager.MdiActiveDocument.Editor         '获取editor对象         Dim values As TypedValue() = {New TypedValue(DxfCode.Operator, "<or"), New TypedValue(DxfCode.Start, "Point"), _                               New TypedValue(DxfCode.Start, "LWPOLYLINE"), New TypedValue(DxfCode.Operator, "or>")}         Dim filter As New SelectionFilter(values)         Dim entOpt As New PromptSelectionOptions         entOpt.MessageForAdding = "请选择要处理的实体"         Dim entRes As PromptSelectionResult = ed.GetSelection(entOpt, filter)         If entRes.Status = PromptStatus.OK Then             Dim sSet As SelectionSet = entRes.Value             Dim pts As New List(Of DBPoint)             Dim plines As New List(Of Polyline)             Using trans As Transaction = db.TransactionManager.StartTransaction()                 Dim bt As BlockTable = trans.GetObject(db.BlockTableId, OpenMode.ForRead)                 Dim btr As BlockTableRecord = trans.GetObject(bt.Item(BlockTableRecord.ModelSpace), OpenMode.ForWrite)                 For Each id As ObjectId In sSet.GetObjectIds                     Dim ent As Entity = trans.GetObject(id, OpenMode.ForRead)                     If TypeOf (ent) Is DBPoint Then                         pts.Add(ent)                     Else                         plines.Add(ent)                     End If                 Next                 For Each pt As DBPoint In pts                     Dim ptPosition As Point2d = New Point2d(pt.Position.X, pt.Position.Y)                     Dim Cdist As Double = 1000 '给一个相当大的值作为比较值                     Dim Cpt As New Point2d                     For Each pline As Polyline In plines                         For i As Integer = 0 To pline.NumberOfVertices - 1                             Dim dist As Double = ptPosition.GetDistanceTo(pline.GetPoint2dAt(i))                             If dist < Cdist Then                                 Cdist = dist                                 Cpt = pline.GetPoint2dAt(i)                             End If                         Next                     Next                     ClosedPt.Add(Cpt)                 Next                 For Each pt1 As Point2d In ClosedPt                     Dim circle As New Circle(New Point3d(pt1(0), pt1(1), 0), Vector3d.ZAxis, 8)                     btr.AppendEntity(circle)                     trans.AddNewlyCreatedDBObject(circle, True)                 Next                 trans.Commit()             End Using         End If     End Sub

各位高手帮我看看，我是新手呀！

single-yu

处理400个点，需要大概5秒中，太慢了！有没有好点的办法呢？我用的平台是VS2005,AutoCad2008！

雪山飞狐_lzh

        [CommandMethod("tt6")]
        public static void test26()
        {

            Document doc = Application.DocumentManager.MdiActiveDocument;
            Editor ed = doc.Editor;
            Database db = doc.Database;

            var resSel =
                ed.SelectAll(
                    new ResultList
                    {
                        { 0, "point,lwpolyline" }
                    });

            List<oint3d> pts = new List<oint3d>();
            List<oint3d> nodes = new List<oint3d>();

            using (var tr = db.TransactionManager.StartTransaction())
            {
                foreach (ObjectId id in resSel.Value.GetObjectIds())
                {
                    Entity ent = tr.GetObject(id, OpenMode.ForRead) as Entity;
                    if (ent is DBPoint)
                    {
                        pts.Add(((DBPoint)ent).Position);
                    }
                    else
                    {
                        Polyline pl = ent as Polyline;
                        for (int i = 0; i < pl.NumberOfVertices; i++)
                        {
                            nodes.Add(pl.GetPoint3dAt(i));
                        }
                    }
                }

                foreach (Point3d pt in pts)
                {
                    Point3d res = nodes.FindByMinKey(p => p.DistanceTo(pt));
                    ed.DrawPoint(res.Convert2d(new Plane()), 2, res.DistanceTo(pt), 8);
                }

            }
        }

single-yu

谢谢版主！

new ResultList{{ 0, "point,lwpolyline" }}和nodes.FindByMinKey(p => p.DistanceTo(pt));是自定义函数吧

能否提供！特别是FindByMinKey！谢了！

雪山飞狐_lzh

是扩展函数，VS要2008版本的哈，

 

        /// <summary>
        /// 按转换函数找出序列中最小键值的对应值
        /// </summary>
        /// <typeparam name="TValue"></typeparam>
        /// <typeparam name="TKey"></typeparam>
        /// <param name="enumerable"></param>
        /// <param name="func"></param>
        /// <returns></returns>
        public static TValue FindByMinKey<TValue, TKey>(this IEnumerable<TValue> enumerable, Func<TValue, TKey> func)
            where TKey : IComparable<TKey>
        {
            var itor = enumerable.GetEnumerator();
            if (!itor.MoveNext())
                throw new ArgumentNullException();
            TValue value = itor.Current;
            TKey key = func(value);
            while (itor.MoveNext())
            {
                TKey tkey = func(itor.Current);
                if (tkey.CompareTo(key) < 0)
                {
                    key = tkey;
                    value = itor.Current;
                }
            }
            return value;
        }

雪山飞狐_lzh

ResultList：
http://bbs.mjtd.com/forum.php?mod=viewthread&tid=79849

 

single-yu

谢谢老大，拜读了！