how to print all qr code in one BtnPrint event

here is code you can try:

protected void PrintButton_Click(object sender, EventArgs e)
{
    foreach (GridViewRow row in YourGridView.Rows)
    {
        // Access data associated with each row
        string qrCodeData = row.Cells[0].Text; // Assuming QR Code data is in the first column

        // Generate QR Code for each row's data
        Bitmap qrCodeImage = GenerateQRCode(qrCodeData); // Use your QR Code generator function

        // Print the QR Code image
        PrintQRCode(qrCodeImage); // Implement the printing logic

        // Dispose the QR Code image to free resources
        qrCodeImage.Dispose();
    }
}
 

Use this

Bitmap qrCodeImage = new Bitmap(200, 200);

private void BtnPrint_Click(object sender, EventArgs e)
{
    // Create a bitmap to hold all QR codes
    int qrCodeWidth = 200; // Width of each QR code
    int qrCodeHeight = 200; // Height of each QR code
    int spacing = 10; // Spacing between QR codes
    int rowCount = GridView1.Rows.Count; // Number of rows in the GridView
    int columnCount = 4; // Number of QR codes to be displayed in each row (adjust as needed)

    int totalWidth = columnCount * qrCodeWidth + (columnCount - 1) * spacing;
    int totalHeight = ((rowCount - 1) / columnCount + 1) * qrCodeHeight + ((rowCount - 1) / columnCount) * spacing;

    Bitmap combinedImage = new Bitmap(totalWidth, totalHeight);

    // Retrieve data from the GridView and generate QR codes
    using (Graphics graphics = Graphics.FromImage(combinedImage))
    {
        int x = 0;
        int y = 0;
        int counter = 0;

        foreach (GridViewRow row in GridView1.Rows)
        {
            // Get the data for each row (e.g., QR code value)
            string qrCodeValue = row.Cells[1].Text; // Use the correct column index

            // Generate QR code image
            BarcodeWriter barcodeWriter = new BarcodeWriter();
            barcodeWriter.Format = BarcodeFormat.QR_CODE;
            barcodeWriter.Options = new ZXing.Common.EncodingOptions
            {
                Width = qrCodeWidth,
                Height = qrCodeHeight
            };

            Bitmap qrCodeImage = barcodeWriter.Write(qrCodeValue);

            // Draw the QR code image on the combined image
            graphics.DrawImage(qrCodeImage, new Rectangle(x, y, qrCodeWidth, qrCodeHeight));

            // Move to the next position
            x += qrCodeWidth + spacing;
            counter++;

            // Move to the next row if necessary
            if (counter % columnCount == 0)
            {
                x = 0;
                y += qrCodeHeight + spacing;
            }
        }
    }

    // Print the combined QR code image
    PrintDocument printDoc = new PrintDocument();
    printDoc.PrintPage += (s, args) =>
    {
        args.Graphics.DrawImage(combinedImage, args.MarginBounds);
        args.HasMorePages = false;
    };

    printDoc.Print();
}

This line error showing

Bitmap qrCodeImage = new Bitmap(placeholderQRCode.Width, placeholderQRCode.Height);

For Placeholder control:

private List GetQRCodeImages()
{
    List qrCodeImages = new List();

    foreach (GridViewRow row in GridView1.Rows)
    {
        Placeholder placeholderQRCode = (Placeholder)row.FindControl("placeholderQRCode");

        // Create a bitmap object and draw the contents of the placeholder onto it
        Bitmap qrCodeImage = new Bitmap(placeholderQRCode.Width, placeholderQRCode.Height);
        placeholderQRCode.RenderControl(new HtmlTextWriter(new StringWriter()));
        using (Graphics graphics = Graphics.FromImage(qrCodeImage))
        {
            IntPtr hdc = graphics.GetHdc();
            placeholderQRCode.RenderControl(new HtmlTextWriter(new HtmlTextWriter(new IntPtr(hdc))));
            graphics.ReleaseHdc(hdc);
        }

        qrCodeImages.Add(qrCodeImage);
    }

    return qrCodeImages;
}

i am using PlaceHolder control  in place of Image in gridview ItemTemplate

Try this

protected void btnPrint_Click(object sender, EventArgs e)
{
    List qrCodeImages = GetQRCodeImages(); // Function to retrieve QR code images from gridview

    int numColumns = 4; // Number of columns in the layout
    int numRows = (int)Math.Ceiling((double)qrCodeImages.Count / numColumns); // Number of rows in the layout

    int qrCodeWidth = 200; // Width of each QR code image
    int qrCodeHeight = 200; // Height of each QR code image

    int combinedImageWidth = qrCodeWidth * numColumns; // Width of the combined image
    int combinedImageHeight = qrCodeHeight * numRows; // Height of the combined image

    Bitmap combinedImage = new Bitmap(combinedImageWidth, combinedImageHeight);

    using (Graphics g = Graphics.FromImage(combinedImage))
    {
        for (int i = 0; i < qrCodeImages.Count; i++)
        {
            int column = i % numColumns;
            int row = i / numColumns;

            int x = column * qrCodeWidth;
            int y = row * qrCodeHeight;

            g.DrawImage(qrCodeImages[i], x, y, qrCodeWidth, qrCodeHeight);
        }
    }

    PrintDocument pd = new PrintDocument();
    pd.PrintPage += (s, args) =>
    {
        args.Graphics.DrawImage(combinedImage, new Point(0, 0));
    };
    pd.Print();
}

private List GetQRCodeImages()
{
    List qrCodeImages = new List();

    foreach (GridViewRow row in GridView1.Rows)
    {
        Image imgQRCode = (Image)row.FindControl("imgQRCode");

        // Convert the Image control to a Bitmap object
        Bitmap qrCodeImage = new Bitmap(imgQRCode.Image);

        qrCodeImages.Add(qrCodeImage);
    }

    return qrCodeImages;
}

All Qr Code should be in one page

Check this

protected void btnPrint_Click(object sender, EventArgs e)
{
    // Loop through all rows in the gridview
    for (int i = 0; i < GridView1.Rows.Count; i++)
    {
        // Get the QR code image from the row
        Image imgQRCode = (Image)GridView1.Rows[i].FindControl("imgQRCode");

        // Print the QR code image
        PrintDocument pd = new PrintDocument();
        pd.PrintPage += (sender, args) =>
        {
            args.Graphics.DrawImage(imgQRCode.Image, new Point(0, 0));
        };
        pd.Print();
    }
}

row.Cells[1].Text; // Use the correct column index

i  used this but still it has ""(blank) value

private void BtnPrint_Click(object sender, EventArgs e)
{
    // Retrieve data from the gridview
    foreach (GridViewRow row in GridView1.Rows)
    {
        // Get the data for each row (e.g., QR code value)
        string qrCodeValue = row.Cells[1].Text; // Use the correct column index

        // Generate QR code image
        BarcodeWriter barcodeWriter = new BarcodeWriter();
        barcodeWriter.Format = BarcodeFormat.QR_CODE;
        barcodeWriter.Options = new ZXing.Common.EncodingOptions
        {
            Width = 200,
            Height = 200
        };

        Bitmap qrCodeImage = barcodeWriter.Write(qrCodeValue);

        // Print the QR code image
        PrintDocument printDoc = new PrintDocument();
        printDoc.PrintPage += (s, args) =>
        {
            args.Graphics.DrawImage(qrCodeImage, args.MarginBounds);
            args.HasMorePages = false;
        };

        printDoc.Print();
    }
}

Always Showing ""(Blank) thst's why not working

string qrCodeValue = row.Cells[0].Text;

using System.Drawing.Printing;
using ZXing;

private void BtnPrint_Click(object sender, EventArgs e)
{
    // Retrieve data from the gridview
    foreach (GridViewRow row in GridView1.Rows)
    {
        // Get the data for each row (e.g., QR code value)
        string qrCodeValue = row.Cells[0].Text;

        // Generate QR code image
        BarcodeWriter barcodeWriter = new BarcodeWriter();
        barcodeWriter.Format = BarcodeFormat.QR_CODE;
        barcodeWriter.Options = new ZXing.Common.EncodingOptions
        {
            Width = 200,
            Height = 200
        };

        Bitmap qrCodeImage = barcodeWriter.Write(qrCodeValue);

        // Print the QR code image
        PrintDocument printDoc = new PrintDocument();
        printDoc.PrintPage += (s, args) =>
        {
            args.Graphics.DrawImage(qrCodeImage, args.MarginBounds);
            args.HasMorePages = false;
        };

        printDoc.Print();
    }
}