I’ve used the excellent iTextSharp library to generate PDFs for different projects. It works very well and has been an excellent tool. One of my recent projects had me needing to generate bar codes for use in a rebate application. The bar code would be the unique rebate ID, used by the mail room scanner to streamline and accelerate the data entry and processing. There are other libraries out there, but since I was already familiar with iTextSharp and knew that it included bar code libraries, I decided to try it out. It was so easy it was nearly ridiculous.

I decided to implement it as an HttpHandler, so that it could be accessible by different applications (including my own). In addition to the bar code, the calling application would also require being passed a unique ID along with some identifying information, which would give minimal security to the page.

It went something like this:

Page.aspx?id=123456&z=12345

Where the 2 parameters would form a unique key that would allow the user to lookup information and get the desired bar code. Inside Page.aspx, I have it calling something like this:

Here is the code for BarCode.ashx:

        public void ProcessRequest(HttpContext context)
        {
            string _barCodeId;

            if (context.Request.QueryString["id"] != null)
            {
                _barCodeId = context.Request.QueryString["id"].ToString();
            }
            else
            {
                throw new ArgumentException("No Bar Code ID specified");
            }

            context.Response.ContentType = "image/jpg";

            System.IO.MemoryStream strm = new System.IO.MemoryStream();
            iTextSharp.text.Document doc = new iTextSharp.text.Document(iTextSharp.text.PageSize.A4, 50, 50, 50, 50);
            iTextSharp.text.pdf.PdfWriter writer = iTextSharp.text.pdf.PdfWriter.GetInstance(doc, strm);
            doc.Open();

            iTextSharp.text.pdf.PdfContentByte cb = writer.DirectContent;
            iTextSharp.text.pdf.Barcode128 code128 = new iTextSharp.text.pdf.Barcode128();
            code128.Code = _barCodeId;
            code128.StartStopText = true;
            code128.GenerateChecksum = false;
            code128.Extended = true;

            code128.CreateDrawingImage(System.Drawing.Color.Black, System.Drawing.Color.White).Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
        }