casting byte[] in c#

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.