dimension extension hideC#

[kmkxperia]

HI I am trying to On and OFF the dimension extension with nearest point selection I tried elow code ut its not suppressing the extension

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace DimLine
{
    public class DimensionExtensionLineToggle
    {
        [CommandMethod("ToggleDimExtensionLine")]
        public void ToggleDimExtensionLine()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Editor ed = doc.Editor;

            // Prompt for entity selection, not filtering here
            PromptEntityOptions opt = new PromptEntityOptions("\nSelect a dimension: ");
            PromptEntityResult res = ed.GetEntity(opt);
            if (res.Status != PromptStatus.OK)
                return;

            using (Transaction tr = doc.TransactionManager.StartTransaction())
            {
                Entity entity = tr.GetObject(res.ObjectId, OpenMode.ForWrite) as Entity;

                // Ensure the selected entity is a dimension
                if (entity is Dimension dim)
                {
                    // Prompt for a point selection near the dimension
                    PromptPointResult pointRes = ed.GetPoint("\nSelect a point near the dimension: ");
                    if (pointRes.Status != PromptStatus.OK)
                        return;

                    Point3d selectedPoint = pointRes.Value;

                    // Get extension line points based on dimension type
                    Point3d? extLine1Start, extLine2Start;
                    GetDimensionExtensionLinePoints(dim, out extLine1Start, out extLine2Start);

                    if (extLine1Start.HasValue && extLine2Start.HasValue)
                    {
                        bool isNear = IsNearDimensionExtensionLine(selectedPoint, extLine1Start.Value, extLine2Start.Value);

                        // Toggle visibility based on proximity
                        ToggleExtensionLines(dim, isNear);

                        tr.Commit();
                    }
                }
                else
                {
                    ed.WriteMessage("\nThe selected entity is not a valid dimension.");
                }
            }
        }

        private void GetDimensionExtensionLinePoints(Dimension dim, out Point3d? extLine1Start, out Point3d? extLine2Start)
        {
            extLine1Start = null;
            extLine2Start = null;

            if (dim is RotatedDimension rotatedDim)
            {
                extLine1Start = rotatedDim.XLine1Point;
                extLine2Start = rotatedDim.XLine2Point;
            }
            else if (dim is AlignedDimension alignedDim)
            {
                extLine1Start = alignedDim.XLine1Point;
                extLine2Start = alignedDim.XLine2Point;
            }
            else if (dim is RadialDimension radialDim)
            {
                extLine1Start = radialDim.Center;
                extLine2Start = radialDim.ChordPoint;
            }
        }

        private bool IsNearDimensionExtensionLine(Point3d selectedPoint, Point3d extLine1Start, Point3d extLine2Start)
        {
            double thresholdDistance = 1.0;

            double distanceToExtLine1 = selectedPoint.DistanceTo(extLine1Start);
            double distanceToExtLine2 = selectedPoint.DistanceTo(extLine2Start);

            return distanceToExtLine1 < thresholdDistance || distanceToExtLine2 < thresholdDistance;
        }

        private void ToggleExtensionLines(Dimension dim, bool isNear)
        {
            string appName = "ExtensionLineToggleApp";
            ObjectId appId = EnsureAppIdRegistered(appName);

            using (ResultBuffer rb = new ResultBuffer(
                new TypedValue((int)DxfCode.ExtendedDataRegAppName, appName),
                new TypedValue((int)DxfCode.ExtendedDataInteger32, isNear ? 1 : 0)
            ))
            {
                dim.XData = rb;
            }

            if (isNear)
            {
                dim.Dimexe = 0.0;
            }
            else
            {
                dim.Dimexe = 1.0;
            }
        }

        private ObjectId EnsureAppIdRegistered(string appName)
        {
            Database db = HostApplicationServices.WorkingDatabase;
            ObjectId appId = ObjectId.Null;

            using (Transaction tr = db.TransactionManager.StartTransaction())
            {
                RegAppTable regAppTbl = tr.GetObject(db.RegAppTableId, OpenMode.ForRead) as RegAppTable;

                if (!regAppTbl.Has(appName))
                {
                    regAppTbl.UpgradeOpen();
                    RegAppTableRecord regAppTblRec = new RegAppTableRecord
                    {
                        Name = appName
                    };
                    appId = regAppTbl.Add(regAppTblRec);
                    tr.AddNewlyCreatedDBObject(regAppTblRec, true);
                }
                else
                {
                    appId = regAppTbl[appName];
                }

                tr.Commit();
            }

            return appId;
        }
    }
}