Why can't I scan the label I received from the printer with the barcode reader?-CodePudding

I create a barcode with the value entered in the Winforms application and print it with the printer. Afterwards, when I want to scan it with a barcode reader, I cannot scan it. This is my code:

private void GenerateBarcodeButton_Click(object sender, EventArgs e)
{
    if (!String.IsNullOrEmpty(textBox1.Text))
    {
        pictureBox1.Image = Zen.Barcode.BarcodeDrawFactory.Code128WithChecksum.Draw(textBox1.Text, 50, 2);
    }
    else
    {
        MessageBox.Show("Please enter the barcode number you want to generate.");
    }
}
public void PrintPicture(object sender, PrintPageEventArgs e)
{
    Bitmap bmp = new Bitmap(pictureBox1.Width, pictureBox1.Height);
    // bmp.SetResolution(203, 203);
    pictureBox1.DrawToBitmap(bmp, new Rectangle(0, 0, pictureBox1.Width, pictureBox1.Height));
    e.Graphics.DrawImage(bmp, 20, 20, new System.Drawing.RectangleF(0, 0, bmp.Width, bmp.Height), System.Drawing.GraphicsUnit.Pixel);
}

private void Print_Click(object sender, EventArgs e)
{
    PrintDialog pd = new PrintDialog();
    PrintDocument pDoc = new PrintDocument();
    pDoc.PrintPage  = PrintPicture;
    pd.Document = pDoc;
    if (pd.ShowDialog() == DialogResult.OK)
    {
        pDoc.Print();
    }
}

The printer model I use for printing is Godex G300. Where did I go wrong?

CodePudding user response：

There is at least one major issue in your code, refer to this Microsoft documentation page to understand how exactly it's done.

When you assign an event handler for PrintPage(), you should wrap it inside a PrintPageEventHandler like this:

pDoc.PrintPage  = new PrintPageEventHandler (this.PrintPicture);

Try doing the above and if it doesn't work, debug it by putting an actual breakpoint inside the PrintPicture() method.

CodePudding user response：

The problem was that I didn't set the DPI. I added this line to the code.

bmp.SetResolution(203, 203);

This is the new method:

        private void PrintPicture(object sender, PrintPageEventArgs e)
        {
            Bitmap bmp = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            bmp.SetResolution(203, 203);
            pictureBox1.DrawToBitmap(bmp, new Rectangle(0, 0, pictureBox1.Width, pictureBox1.Height));
            e.Graphics.DrawImage(bmp, 38, 10);
            bmp.Dispose();
        }