converting Byte array to a string

[EyeTalion]

I'm using this code to view a .PDF that is stroed in a DB:

  Response.ContentType = "application/octet-stream"
            ' let the browser know the file name
            Response.AddHeader("Content-Disposition", "attachment;filename=" & Trim(pdf))
            ' let the browser know the file size
            Response.AddHeader("Content-Length", strFileName)
            Response.BinaryWrite(objDR("bid_document"))

but I'm having trouble getting the filesize in the Response.AddHeader("Content-Length", strFileName)
the only way I can get the file size is objDR("pdfFile") but then I can't place that value in there becasue you can't convert Byte() array to a string...any suggestions on how I can get the file size? If I put it in manually it works fine...