eAlreadyInDb error in C# Autocad

[nguyenvannhuan90123780339]

I want to modify my attdef value but my code returns an error on sentence : "acBlktblRec.AppendEntity(acText);". error is : "eAlreadyInDb"

This is my code:

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

namespace LinkedIn
{
    public class Initialization : IExtensionApplication
    {
        #region Commands

        [CommandMethod("LISelectSet")]
        public void cmdEdSelectSet()
        {
            Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
            Database db = HostApplicationServices.WorkingDatabase;
            // get the value  enterd from user 

            PromptStringOptions pstringopt = new PromptStringOptions("\nEnter the string:");
            //pstringopt.Message = "\nEnter the string";
            pstringopt.AllowSpaces = true;
            string ResStringInput;
            PromptResult prstringress = ed.GetString(pstringopt);

            if (prstringress.Status != PromptStatus.OK) return;
            ResStringInput = prstringress.StringResult;

            PromptSelectionOptions prSelOpts = new PromptSelectionOptions();
            prSelOpts.AllowDuplicates = false;
            prSelOpts.MessageForAdding = "\nSelect dimention to measure";
            prSelOpts.MessageForRemoval = "\nselect dimention to remove from selection";
            prSelOpts.RejectObjectsFromNonCurrentSpace = false;
            prSelOpts.RejectObjectsOnLockedLayers = true;
            //prSelOpts.RejectPaperspaceViewport = true;
            List<string> list = new List<string>();
            TypedValue[] tValues = new TypedValue[1];
            tValues[0] = new TypedValue((int)DxfCode.Start, "Dimension");
            SelectionFilter selfil = new SelectionFilter(tValues);

            PromptSelectionResult prSelRes = ed.GetSelection(prSelOpts, selfil);
            if (prSelRes.Status != PromptStatus.OK) return;
            Transaction trans = db.TransactionManager.StartTransaction();
            SelectionSet selSet = prSelRes.Value;
            Dimension dimentionobj;
            double lenTotal = 0.0;
            string lenelement;
            //List<string> list = new List<string>();
            foreach (SelectedObject selObj in selSet)
            {
                dimentionobj = trans.GetObject(selObj.ObjectId, OpenMode.ForRead) as Dimension;
                lenTotal += dimentionobj.Measurement;
                lenelement = ResStringInput + " x " + dimentionobj.Measurement.ToString();
                list.Add(lenelement);
            }
            DBText acText = new DBText();
            acText.SetDatabaseDefaults();
            string[] terms = list.ToArray();
            string[] animals2 = new string[] { "deer", "moose", "boars" };
            int n = 0;
            foreach (String item in animals2)
            {
                Database acCurDb = Application.DocumentManager.MdiActiveDocument.Database;
                BlockTable acBlkTbl;
                acBlkTbl = trans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead) as BlockTable;
                BlockTableRecord acBlktblRec;
                acBlktblRec = trans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace], OpenMode.ForWrite) as BlockTableRecord;
                ed.WriteMessage(item);                
                acText.Position = new Point3d(23, 11 + n * 4, 0);
                acText.Height = 3.5;
                acText.TextString = item;
                n = n + 1;
                acBlktblRec.AppendEntity(acText);
                trans.AddNewlyCreatedDBObject(acText, true);
            }
            trans.Commit();
        }

        #endregion


        #region Initialization

        void IExtensionApplication.Initialize()
        {
            Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
            AssemblyName appName = Assembly.GetExecutingAssembly().GetName();

            object[] attrs = Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(AssemblyTitleAttribute), false);
            ed.WriteMessage(((AssemblyTitleAttribute)attrs[0]).Title + " " +
                appName.Version.Major + "." + appName.Version.MajorRevision + "." +
                appName.Version.Minor + " is loaded...");
        }

        void IExtensionApplication.Terminate()
        {

        }
        #endregion

    }
}