how to create qr code in razor page

Yulia Chive

3 min read

·

07-12-2024

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Generating QR Codes in Razor Pages: A Step-by-Step Guide

Creating QR codes dynamically within your Razor Pages application offers a powerful way to engage users and provide convenient access to information. This guide will walk you through the process, using a combination of C# libraries and Razor syntax to seamlessly integrate QR code generation into your pages.

1. Choosing a QR Code Library:

Several excellent .NET libraries simplify QR code generation. For this example, we'll use QRCode.Net, a popular and well-maintained option. You can install it via NuGet Package Manager:

Install-Package QRCoder

2. Creating the QR Code Generator:

Let's build a simple C# class to handle QR code generation. This class encapsulates the logic, making it reusable across your Razor Pages:

using QRCoder;

public class QRCodeGenerator
{
    public static byte[] GenerateQRCode(string data, int size = 256)
    {
        QRCodeGenerator qrGenerator = new QRCodeGenerator();
        QRCodeData qrCodeData = qrGenerator.CreateQrCode(data, QRCodeGenerator.ECCLevel.Q);
        QRCode qrCode = new QRCode(qrCodeData);
        BitmapByteQRCode qrCodeImage = qrCode.GetGraphic(size, Color.Black, Color.White, null, 2, true); 
        return qrCodeImage.Data;
    }
}

This QRCodeGenerator class takes the data (text or URL) and an optional size parameter as input. It utilizes the QRCoder library to create the QR code as a bitmap and returns it as a byte array. The ECCLevel.Q setting provides a good balance between error correction and code size. Adjust as needed for your application.

3. Displaying the QR Code in your Razor Page:

Now, let's integrate this into a Razor Page. Assume you have a page called GenerateQRCode.cshtml. Here's how you might incorporate the QR code generation:

@page
@model GenerateQRCodeModel

<h1>Generate QR Code</h1>

<form method="post">
    <label for="data">Enter Data (Text or URL):</label>
    <input type="text" asp-for="Data" id="data" />
    <button type="submit">Generate QR Code</button>
</form>

@if (!string.IsNullOrEmpty(Model.QrCodeData))
{
    <img src="data:image/png;base64,@Convert.ToBase64String(Model.QrCodeData)" alt="QR Code" />
}

@code {
    [BindProperty]
    public string Data { get; set; } = "";

    [BindProperty]
    public byte[] QrCodeData { get; set; }

    public void OnPost()
    {
        QrCodeData = QRCodeGenerator.GenerateQRCode(Data);
    }
}

Explanation:

• The page uses a form to accept user input (Data).
• On form submission (OnPost), the QRCodeGenerator is called to produce the QR code.
• The generated QrCodeData (byte array) is then converted to a Base64 string and used as the src attribute of an <img> tag. This allows you to display the QR code directly within the browser.

4. Adding Error Handling and Customization:

For a production-ready solution, add error handling to gracefully manage invalid input. You could also enhance the QRCodeGenerator class to offer more customization options (e.g., logo embedding, color schemes).

5. Further Enhancements:

• Download functionality: Allow users to download the generated QR code as a PNG image. This can be achieved by adding a download link that uses the Base64 encoded data.
• Dynamic data sources: Instead of user input, fetch data from a database or other source to dynamically generate QR codes for different items.
• Styling: Use CSS to style the QR code's container and improve the overall look and feel.

This comprehensive guide provides a solid foundation for integrating QR code generation into your Razor Pages application. Remember to install the QRCoder NuGet package and tailor the code to your specific requirements. By following these steps, you can easily add this valuable feature to enhance user experience and functionality in your web applications.