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Barcodes in ASP.NET applications

Erick Cuellar

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21 Oct 2008

Easy and cheap barcodes in ASP.NET.

Introduction

In one of my projects, I needed to implement barcodes into an ASP.NET page. Unfortunately, the only way that I found was using a third party component. So, I decided to find a way to do it without using external components.

Using the code

First, you have to download a free barcode font. For this example, I used "IDAutomationHC39M" from IdAutomation. In this example, I used Barcode 39.

In WinForms applications, it is really easy to use Barcode fonts; just place a Label, and apply the free barcode font, and assign a value, and everything is ready.

In Webforms, things are different, because the application runs on the server. The barcode font must reside on the server. If we use a Label, the barcode font is located on the server, not on the client, so you will just see the value, not the barcode.

Well, let's start:

Just copy the barcode font into the windows\fonts folder of the server. The whole idea is to create a text with the font (a barcode), then create an image of it, and send it back to the client.

Here is a simple page with it:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Barcodes
{

/// <summary />
/// Summary description for BarCode.
/// </summary />

public class BarCode : System.Web.UI.Page
{
    private void Page_Load(object sender, System.EventArgs e)
    {
         // Get the Requested code to be created.
         string Code = Request["code"].ToString();

         // Multiply the lenght of the code by 40 (just to have enough width)
         int w = Code.Length * 40;
    
        // Create a bitmap object of the width that we calculated and height of 100
         Bitmap oBitmap = new Bitmap(w,100);
    
        // then create a Graphic object for the bitmap we just created.
         Graphics oGraphics = Graphics.FromImage(oBitmap);
        
        // Now create a Font object for the Barcode Font
        // (in this case the IDAutomationHC39M) of 18 point size
        Font oFont = new Font("IDAutomationHC39M", 18);
        
        // Let's create the Point and Brushes for the barcode
        PointF oPoint = new PointF(2f, 2f);
         SolidBrush oBrushWrite = new SolidBrush(Color.Black);
         SolidBrush oBrush = new SolidBrush(Color.White);
            
        // Now lets create the actual barcode image
        // with a rectangle filled with white color
        oGraphics.FillRectangle(oBrush, 0, 0, w, 100);
            
        // We have to put prefix and sufix of an asterisk (*),
        // in order to be a valid barcode
        oGraphics.DrawString("*" + Code + "*", oFont, oBrushWrite, oPoint);
        
        // Then we send the Graphics with the actual barcode
        Response.ContentType = "image/jpeg" ;
         oBitmap.Save (Response.OutputStream, ImageFormat.Jpeg);
    }
}
}

Let's test our page. Just call http://localhost/BarCodes/BarCode.aspx?Code=1234.

As you can see, there is a barcode with the value of 1234.

Now, let’s create a page that has an asp:Image on it:

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" 
   AutoEventWireup="false" Inherits="BarCodes.WebForm1" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
 <HEAD>
  <title>WebForm1</title>
  <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
  <meta name="CODE_LANGUAGE" Content="C#">
  <meta name="vs_defaultClientScript" content="JavaScript">
  <meta name="vs_targetSchema" 
        content="http://schemas.microsoft.com/intellisense/ie5">
 </HEAD>
 <body MS_POSITIONING="GridLayout">
  <form id="Form1" method="post" runat="server">
   <asp:Image id="myBarCode"  runat="server"></asp:Image>
  </form>
 </body>
</HTML>

Add this to the code behind:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace BarCodes
{
    /// <summary />
    /// Summary description for WebForm1.
    /// </summary />
    public class WebForm1 : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Image myBarCode;
    
        private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
            myBarCode.ImageUrl = "BarCode.aspx?code=31231";
        }

        #region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /// <summary />
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary />
        private void InitializeComponent()
        {    
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion
    }
}

Now, let’s see the result:

Well friends, that is all! An easy and cheap way to have barcodes in your ASP.NET applications.

License

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