LINQ Transaction, Commit And Roll Back not working,why

 I want to implement Transcation,commit and roll back but in first table data not removed after getting time out ,which break point goes to exception block, and any standard way to write this api method

async Task IMaterialManager.AddVersionDetails(AddVersionData AppItem)
{
    string Action = string.Empty;
    _ResponseStatus = new ResponseStatus();
    var IsValidFile = false;
    var FileNameByUser = String.Empty;
    var FileExtension = String.Empty;
    var FileUniqueName = String.Empty;
    var FileBase64 = String.Empty;
    var FileOriginalNameWithPath = String.Empty;

    using (var context = new LmsDocumentManagerContext())
    {
        using (var dbContextTransaction = context.Database.BeginTransaction())
        {
            try
            {
                var createDate = DateTime.UtcNow.Add(new TimeSpan(+5, +30, +00));
                var MaxVersion = (from VersionDetails in _dbContext.VersionDetails.GroupBy(x => x.ContentId).Select(k => new { ContentId = k.Key, VersionName = k.Max(p => p.VersionName) })
                                  where VersionDetails.ContentId == AppItem.ContentId
                                  select new
                                  {
                                      ContentId = VersionDetails.ContentId,
                                      VersionName = VersionDetails.VersionName
                                  });
                var ContentDetailsItem = _dbContext.ContentDetails.Where(k => k.Id == AppItem.ContentId).FirstOrDefault();
                if (ContentDetailsItem != null)
                {

                    var Item = new VersionDetails();
                    if (AppItem.FileTypeId == (int)FileType.Document)
                    {
                        IsValidFile = IsValidUpload(AppItem.FileNameByUserBase).Result;
                        if (IsValidFile)
                        {
                            FileNameByUser = AppItem.FileNameByUser;
                            FileExtension = Path.GetExtension(AppItem.FileNameByUser);
                            FileUniqueName = GetUniqueFileName(FileNameByUser, FileExtension, MaterialType.StudyMatetial.ToString());
                            FileBase64 = AppItem.FileNameByUserBase;
                            FileOriginalNameWithPath = Path.Combine(_DocumentPath.UploadPathStudyMaterial, FileUniqueName);
                            Base64ToOriginalFile(FileBase64, FileOriginalNameWithPath);
                        }
                    }
                    int IncrementedVersion = (Convert.ToInt32(MaxVersion.FirstOrDefault().VersionName) + 1);
                    Item.ContentId = AppItem.ContentId;
                    Item.VersionName = Convert.ToString(IncrementedVersion);
                    Item.FileNameByUser = FileNameByUser;
                    Item.FilePhysicalDirectoryId = FileUniqueName;
                    if (AppItem.FileTypeId == (int)FileType.Link)
                    {
                        Item.FilePath = AppItem.Link;
                    }
                    if (AppItem.FileTypeId == (int)FileType.Document)
                    {
                        Item.FilePath = FileOriginalNameWithPath;
                    }
                    Item.VersionNote = AppItem.VersionNote;
                    Item.FilePhysicalDirectoryId = FileUniqueName;
                    Item.CreatedBy = _authenticationManager.GetAuthenticatedUser().Result.UserId;
                    Item.CreatedOn = createDate;
                    _dbContext.VersionDetails.Add(Item);
                    var result = await _dbContext.SaveChangesAsync();
                    var LatestVersionId = _dbContext.VersionDetails.OrderByDescending(u => u.VersionId).FirstOrDefault();

                    if (result > 0)
                    {
                        ContentDetailsItem.FileType = AppItem.FileType;
                        ContentDetailsItem.FileTypeId = AppItem.FileTypeId;
                        ContentDetailsItem.LatestVersionId = LatestVersionId.VersionId;
                        ContentDetailsItem.LatestVersionName = Convert.ToString(IncrementedVersion);

                        if (AppItem.FileTypeId == (int)FileType.Link)
                        {
                            ContentDetailsItem.LatestFileNameByUser = "";
                            ContentDetailsItem.LatestFilePhysicalDirectoryId = "";
                            ContentDetailsItem.LatestFilePath = AppItem.Link;
                        }
                        if (AppItem.FileTypeId == (int)FileType.Document)
                        {
                            ContentDetailsItem.LatestFileNameByUser = AppItem.FileNameByUser;
                            ContentDetailsItem.LatestFilePhysicalDirectoryId = FileUniqueName;
                            ContentDetailsItem.LatestFilePath = FileOriginalNameWithPath;
                        }
                        ContentDetailsItem.FileTypeId = AppItem.FileTypeId;
                        ContentDetailsItem.ModifiedOn = createDate;
                        ContentDetailsItem.ModifiedBy = _authenticationManager.GetAuthenticatedUser().Result.UserId;
                        _dbContext.ContentDetails.Update(ContentDetailsItem);


                        #region ActionLog
                        var AddActionLog = new ActionLog();
                        var MaxVersionId = (from VersionDetails in _dbContext.VersionDetails.GroupBy(x => x.VersionId).Select(k => new { VersionId = k.Key, ContentId = k.Max(p => p.ContentId) })
                                            where VersionDetails.ContentId == Item.ContentId
                                            select new
                                            {
                                                VersionId = VersionDetails.VersionId,
                                                ContentId = VersionDetails.ContentId ?? 0

                                            }).OrderByDescending(k => k.VersionId).FirstOrDefault();
                        var _ContentTopic = (from ContentTopic in _dbContext.ContentDetails.Where(k => k.Id == MaxVersionId.ContentId)
                                             select new
                                             {
                                                 ContentTopic.Topic
                                             }).FirstOrDefault();


                        var _ContentVersionName = (from ContentVersionName in _dbContext.VersionDetails.Where(k => k.VersionId == MaxVersionId.VersionId)
                                                   select new
                                                   {
                                                       ContentVersionName.VersionName
                                                   }).FirstOrDefault();

                        AddActionLog.ContentId = MaxVersionId.ContentId;
                        AddActionLog.VersionId = MaxVersionId.VersionId;
                        AddActionLog.Action = "New Content Upload";
                        AddActionLog.Comment = _ContentTopic.Topic + "(Version:-" + _ContentVersionName.VersionName + ")";
                        AddActionLog.CreatedBy = _authenticationManager.GetAuthenticatedUser().Result.UserId;
                        AddActionLog.CreatedOn = createDate;
                        _dbContext.ActionLog.Add(AddActionLog);
                        #endregion
                    }
                    else
                    {

                        _ResponseStatus.Status = (int)HttpStatusCode.InternalError;
                        _ResponseStatus.ErrorMessage = ErrorMsg.InternalServerError;
                    }
                }
                else
                {
                    _ResponseStatus.Status = (int)HttpStatusCode.NotValid;
                    _ResponseStatus.ErrorMessage = ErrorMsg.ContentNotExist;
                }


                var result1 = await _dbContext.SaveChangesAsync();
                if (result1 > 0)
                {
                    _ResponseStatus.Status = (int)HttpStatusCode.Sucess;
                    _ResponseStatus.ErrorMessage = SuccessMsg.VersionAddMsg;
                }
                else
                {
                    _ResponseStatus.Status = (int)HttpStatusCode.InternalError;
                    _ResponseStatus.ErrorMessage = ErrorMsg.InternalServerError;
                }
                dbContextTransaction.Commit();
            }

            catch (Exception ex)
            {
                dbContextTransaction.Rollback();
            }
        }
    }
    return _ResponseStatus;
}