在autocad.NET中使用Point3AngularDimension创建3点角度标注

//by 鸟哥 qq1833183060
//qq群 720924083
//2020-11-09
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.Windows;
using Autodesk.AutoCAD.Geometry;
namespace AcadDemo
{
    public class DimensionDemo
    {
        //https://adndevblog.typepad.com/autocad/2012/04/creating-a-3-point-angular-dimension-using-point3angulardimension-in-net.html
        [CommandMethod("netDimAngular")]
        public void netDimAngular()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;
            Editor ed = doc.Editor;

            PromptEntityOptions peo = new PromptEntityOptions("nSelect an Arc: ");

            peo.SetRejectMessage("nMust be an Arc...");

            peo.AddAllowedClass(typeof(Arc), true);

            PromptEntityResult per = ed.GetEntity(peo);

            if (per.Status != PromptStatus.OK)
                return;

            using (Transaction Tx =db.TransactionManager.StartTransaction())
            {
                Arc arc = Tx.GetObject(per.ObjectId, OpenMode.ForRead) as Arc;

                BlockTable bt = Tx.GetObject(db.BlockTableId,OpenMode.ForRead) as BlockTable;

                BlockTableRecord btr = Tx.GetObject(bt[BlockTableRecord.ModelSpace],OpenMode.ForWrite) as BlockTableRecord;

                string dimStyle = "Standard";

                DimStyleTable dimStyleTable = Tx.GetObject(db.DimStyleTableId,OpenMode.ForRead) as DimStyleTable;

                if (dimStyleTable.Has(dimStyle))
                {
                    Point3d point3 =arc.StartPoint.Add(arc.EndPoint.GetAsVector()).MultiplyBy(0.5);

                    ObjectId dimStyleId = dimStyleTable[dimStyle];

                    Point3AngularDimension dim = new Point3AngularDimension(arc.Center,arc.StartPoint,arc.EndPoint,point3, "",dimStyleId);

                    btr.AppendEntity(dim);

                    Tx.AddNewlyCreatedDBObject(dim, true);
                    Tx.Commit();

                }
            }
        }
    }
}