Select polyline segment

[krkeec763189]

Hi

I want to make routine to select polyline segment?


what Am I doing wrong?

Problem is in this line:

Dim nestedObject As DBObject = nestedResults.ObjectId.GetObject(OpenMode.ForRead)

i alwasy get exeption here: Object reference not set to an instance of an object

 Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Dim doc As Document = DocumentManager.MdiActiveDocument
        Dim db As Database = doc.Database
        Dim ed As Editor = doc.Editor
        Dim rad As Double = 40 * ppc / 1000
        Dim nestedOptions As New PromptNestedEntityOptions("Odaberi segment: ")
        nestedOptions.AllowNone = False
        Dim nestedResults As PromptNestedEntityResult = ed.GetNestedEntity(nestedOptions)
        If nestedResults.Status = PromptStatus.OK Then
            Dim nestedObject As DBObject = nestedResults.ObjectId.GetObject(OpenMode.ForRead)
            If nestedObject.[GetType]().Equals(GetType(Polyline)) Then
                MsgBox("nije polyline")
                Dim plineEntity As Polyline = DirectCast(nestedObject, Polyline)
                Dim searchPoint As Point2d = plineEntity.GetClosestPointTo(nestedResults.PickedPoint, False).Add(plineEntity.StartPoint.GetAsVector()).Convert2d(plineEntity.GetPlane())
                Dim segmentIndex As Integer
                For segmentIndex = 0 To plineEntity.NumberOfVertices - 2
                    If plineEntity.OnSegmentAt(segmentIndex, searchPoint, 0.0) Then
                        Exit For
                    End If
                Next
                Dim lineSegment As LineSegment3d = plineEntity.GetLineSegmentAt(segmentIndex)
                MsgBox("Broj segmenta je: " & segmentIndex + 1)
            Else
                MsgBox("nije polyline")
                Exit Sub
            End If


        End If
    End Sub
End Class

Please help.

KK

[fixo]

Explain us what is your goal, because from your code
is too difficult to understand you steps,
btw, small picture may help to see that, so make
a screenshot from drawing and upload here

[peter]

My first observation is you are trying to do something with your open for read object, usually in .net that would require a transaction...

Remember this is managed code!

I haven't tested it but it might something this below.

P=

Hi

I want to make routine to select polyline segment?


what Am I doing wrong?

Problem is in this line:

Dim nestedObject As DBObject = nestedResults.ObjectId.GetObject(OpenMode.ForRead)

i alwasy get exeption here: Object reference not set to an instance of an object

 Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Dim doc As Document = DocumentManager.MdiActiveDocument
        Dim db As Database = doc.Database
        Dim ed As Editor = doc.Editor
        Dim rad As Double = 40 * ppc / 1000
        Dim nestedOptions As New PromptNestedEntityOptions("Odaberi segment: ")
        nestedOptions.AllowNone = False
        Dim nestedResults As PromptNestedEntityResult = ed.GetNestedEntity(nestedOptions)

        Dim tr as transaction = db.TransactionManager.StartTransaction()

        If nestedResults.Status = PromptStatus.OK Then

            Using tr

            Dim nestedObject As DBObject = nestedResults.ObjectId.GetObject(OpenMode.ForRead)
            If nestedObject.[GetType]().Equals(GetType(Polyline)) Then
                MsgBox("nije polyline")
                Dim plineEntity As Polyline = DirectCast(nestedObject, Polyline)
                Dim searchPoint As Point2d = plineEntity.GetClosestPointTo(nestedResults.PickedPoint, False).Add(plineEntity.StartPoint.GetAsVector()).Convert2d(plineEntity.GetPlane())
                Dim segmentIndex As Integer
                For segmentIndex = 0 To plineEntity.NumberOfVertices - 2
                    If plineEntity.OnSegmentAt(segmentIndex, searchPoint, 0.0) Then
                        Exit For
                    End If
                Next
                Dim lineSegment As LineSegment3d = plineEntity.GetLineSegmentAt(segmentIndex)


                MsgBox("Broj segmenta je: " & segmentIndex + 1)
            Else
                MsgBox("nije polyline")
                Exit Sub
            End If


            tr.commit
            End Using


        End If
    End Sub
End Class

Please help.

KK

[_gile]

Hi,

If I do not misunderstand what you're trying to do (prompt for selecting a nested polyline and get the selected segment on polyline), here's a way which will work whatever the nesting level (even not nested at all).

C#

        public void SelectNestedPolyline()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;
            Editor ed = doc.Editor;

            // Prompt the user to select a polyline segment.
            PromptNestedEntityOptions options =
                new PromptNestedEntityOptions("\nSelect a polyline segment: ");
            options.AllowNone = false;
            PromptNestedEntityResult result = ed.GetNestedEntity(options);
            if (result.Status != PromptStatus.OK)
                return;

            // If the selected entity is a polyline.
            if (result.ObjectId.ObjectClass.Name == "AcDbPolyline")
            {
                // Start a transaction to open the selected polyline.
                using (Transaction tr = db.TransactionManager.StartTransaction())
                {
                    // Transform the picked point from current UCS to WCS.
                    Point3d wcsPickedPoint = result.PickedPoint.TransformBy(ed.CurrentUserCoordinateSystem);

                    // Open the polyline.
                    Polyline pline = (Polyline)tr.GetObject(result.ObjectId, OpenMode.ForRead);

                    // Get the closest point to picked point on the polyline.
                    // If the polyline is nested, it's needed to transform the picked point using the 
                    // the transformation matrix that is applied to the polyline by its containers.
                    Point3d pointOnPline = result.GetContainers().Length == 0 ?
                        pline.GetClosestPointTo(wcsPickedPoint, false) : // not nested polyline
                        pline.GetClosestPointTo(wcsPickedPoint.TransformBy(result.Transform.Inverse()), false); // nested polyline

                    // Get the selected segment index.
                    int segmentIndex = (int)pline.GetParameterAtPoint(pointOnPline);
                    ed.WriteMessage("\nSelected segment index: {0}", segmentIndex);
                    tr.Commit();
                }
            }
        }

VB

        Public Sub SelectNestedPolyline()
            Dim doc As Document = Application.DocumentManager.MdiActiveDocument
            Dim db As Database = doc.Database
            Dim ed As Editor = doc.Editor

            ' Prompt the user to select a polyline segment.
            Dim options As New PromptNestedEntityOptions(vbLf & "Select a polyline segment: ")
            options.AllowNone = False
            Dim result As PromptNestedEntityResult = ed.GetNestedEntity(options)
            If result.Status <> PromptStatus.OK Then
                Return
            End If

            ' If the selected entity is a polyline.
            If result.ObjectId.ObjectClass.Name = "AcDbPolyline" Then

                ' Start a transaction to open the selected polyline.
                Using tr As Transaction = db.TransactionManager.StartTransaction()

                    ' Transform the picked point from current UCS to WCS.
                    Dim wcsPickedPoint As Point3d = result.PickedPoint.TransformBy(ed.CurrentUserCoordinateSystem)

                    ' Open the polyline.
                    Dim pline As Polyline = DirectCast(tr.GetObject(result.ObjectId, OpenMode.ForRead), Polyline)

                    ' Get the closest point to picked point on the polyline.
                    ' If the polyline is nested, it's needed to transform the picked point using the 
                    ' the transformation matrix that is applied to the polyline by its containers.
                    Dim pointOnPline As Point3d = _
                        If(result.GetContainers().Length = 0, _
                            pline.GetClosestPointTo(wcsPickedPoint, False), _
                            pline.GetClosestPointTo(wcsPickedPoint.TransformBy(result.Transform.Inverse()), False))

                    ' Get the selected segment index.
                    Dim segmentIndex As Integer = CInt(pline.GetParameterAtPoint(pointOnPline))
                    ed.WriteMessage(vbLf & "Selected segment index: {0}", segmentIndex)
                    tr.Commit()
                End Using
            End If
        End Sub

F#

let SelectNestedPolyline () =
    let doc = Application.DocumentManager.MdiActiveDocument
    let db = doc.Database
    let ed = doc.Editor

    // Prompt the user to select a polyline segment.
    let options = new PromptNestedEntityOptions("\nSelect a polyline segment: ")
    options.AllowNone <- false
    let result = ed.GetNestedEntity(options)

    // If the selected entity is a polyline.
    if result.Status = PromptStatus.OK && 
        result.ObjectId.ObjectClass.Name = "AcDbPolyline" then

        // Start a transaction to open the selected polyline
        use tr = db.TransactionManager.StartTransaction()

        // Transform the picked point from current UCS to WCS.
        let wcsPickedPoint = result.PickedPoint.TransformBy(ed.CurrentUserCoordinateSystem)
        
        // Open the polyline.
        let pline = tr.GetObject(result.ObjectId, OpenMode.ForRead) :?> Polyline

        // Get the closest point to picked point on the polyline.
        // If the polyline is nested, it's needed to transform the picked point using the 
        // the transformation matrix that is applied to the polyline by its containers.
        let pointOnPline =
            if result.GetContainers().Length = 0 then pline.GetClosestPointTo(wcsPickedPoint, false) 
            else pline.GetClosestPointTo(wcsPickedPoint.TransformBy(result.Transform.Inverse()), false);

        // Get the selected segment index.
        let segmentIndex = int (pline.GetParameterAtPoint(pointOnPline))
        ed.WriteMessage("\nSelected segment index: {0}", segmentIndex)

        tr.Commit()