casting byte[] in c#

Question

I need to insert to database a varbinary type. In my code behind, I created a method which will insert the data.:

private void insertAudioFiles()
        {
            ResourcesAudioDataModel audio = new ResourcesAudioDataModel();
            ResourceDataAccess insert = new ResourceDataAccess();
            using(BinaryReader br = new BinaryReader(FileUpload2.PostedFile.InputStream))
            {
                string GL = lblGrLvlId.Text;
                string sub = ddlSubject.SelectedValue;
                string week = ddlWeekNo.SelectedValue;
                string teacher = lblID.Text;
                string type = Path.GetFileName(FileUpload2.PostedFile.FileName);
                byte[] bytes = br.ReadBytes((int)FileUpload2.PostedFile.InputStream.Length);

                audio.GradeLevelId = Convert.ToInt32(gl.ToString());
                audio.SubjectId = Convert.ToInt32(sub.ToString());
                audio.WeekNo = week.ToString();
                audio.TeacherId = Convert.ToInt32(lblID.ToString());
                audio.ContentType = type.ToString();
                audio.Data = Convert.ToInt32(bytes);
            }

        }

 I have an error in line 19 (audio.Data = Convert.ToInt32(bytes);). Tried to changed it to audio.Data = Convert.ToByte[](bytes); but still no luck. Can anyone share your knowledge? Thanks a lot.