In this article I will explain with an example, how to use dynamically generate and display QR Code image using ASP.Net in C# and VB.Net.
For generating QR Codes I will make use of QRCoder which is an Open Source Library QR code generator.
 
 

QR Code Library

You will need to download the QR code library from the following location and open the project in Visual Studio and build it. Once it is build, you can find the DLL in the Debug folder.
Download QRCoder
Note: You can also find the QRCoder DLL in the attached sample project.
 
 

HTML Markup

The HTML Markup consists of following control:
TextBox – For capturing barcode.
Button – For generate QR code.
PlaceHolder – generated QR code image displayed here.
 
<asp:TextBox ID="txtCode" runat="server"></asp:TextBox>
<asp:Button ID="btnGenerate" runat="server" Text="Generate" OnClick="btnGenerate_Click" />
<hr />
<asp:PlaceHolder ID="plBarCode" runat="server" />
 
 

Namespaces

You will need to import the following namespaces.
C#
using QRCoder;
using System.IO;
using System.Drawing;
 
VB.Net
Imports QRCoder
Imports System.IO
Imports System.Drawing
 
 

Generating and displaying QR code image in ASP.Net

Inside the Button Click event handler, The Text from the TextBox is passed to the CreateQRCode method of the QRCoder library which returns a Bitmap image.
Finally, saved as PNG image in MemoryStream which later is converted to a base64 string and displayed on the page using an Image control.
C#
protected void btnGenerate_Click(object sender, EventArgs e)
{
    string code = txtCode.Text;
    QRCodeGenerator qrGenerator = new QRCodeGenerator();
    QRCodeGenerator.QRCode qrCode = qrGenerator.CreateQrCode(code, QRCodeGenerator.ECCLevel.Q);
    System.Web.UI.WebControls.Image imgBarCode = new System.Web.UI.WebControls.Image();
    imgBarCode.Height = 150;
    imgBarCode.Width = 150;
    using (Bitmap bitMap = qrCode.GetGraphic(20))
    {
        using (MemoryStream ms = new MemoryStream())
        {
            bitMap.Save(ms,System.Drawing.Imaging.ImageFormat.Png);
            byte[]byteImage = ms.ToArray();
            imgBarCode.ImageUrl = "data:image/png;base64," + Convert.ToBase64String(byteImage);
        }
        plBarCode.Controls.Add(imgBarCode);
    }
}
 
VB.Net
Protected Sub btnGenerate_Click(sender As Object, e As EventArgs)
    Dim code As String = txtCode.Text
    Dim qrGenerator As New QRCodeGenerator()
    Dim qrCode As QRCodeGenerator.QRCode = qrGenerator.CreateQrCode(code, QRCodeGenerator.ECCLevel.Q)
    Dim imgBarCode As New System.Web.UI.WebControls.Image()
    imgBarCode.Height = 150
    imgBarCode.Width = 150
    Using bitMap As Bitmap = qrCode.GetGraphic(20)
        Using ms As New MemoryStream()
            bitMap.Save(ms,System.Drawing.Imaging.ImageFormat.Png)
            Dim byteImage As Byte() = ms.ToArray()
            imgBarCode.ImageUrl = "data:image/png;base64," + Convert.ToBase64String(byteImage)
        End Using
        plBarCode.Controls.Add(imgBarCode)
    End Using
End Sub
 
 

Screenshot

Dynamically generate and display QR code Image in ASP.Net
 
 

Demo

View Demo
 
 

Downloads

Download Code