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private void button_druck_Click(object sender, EventArgs e)
{
    if (!(pictureBox_Hintergrund.BackgroundImage == null))
    {
        if (printDialog1.ShowDialog() == DialogResult.OK)
        {
            printDocument1.Print();
        } 
    }
}

private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
    e.Graphics.DrawImage(pictureBox_Hintergrund.BackgroundImage, 0, 0, pictureBox_Hintergrund.Width, pictureBox_Hintergrund.Height);
    // an diese stelle müßte ich wohl eine schleife haben, die jeine "new_" box nach der anderen hinzu fügt.
}					

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var CountOfMyLovelyPictureBoxes = MyLovelyParentControl.Controls.OfType<PictureBox>().Where(x => x.Name.StartsWith("new_")).Count();					

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var CountOfMyLovelyPictureBoxes = Controls.OfType<PictureBox>().Where(x => x.Name.StartsWith("new_")).Count();
label1.Text = CountOfMyLovelyPictureBoxes.ToString() + " new_";					

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private PictureBox[] boxen;
// am ende vom links und rechtsklick ereigniss.
boxen = Controls.OfType<PictureBox>().Where(x => x.Name.StartsWith("new_")).ToArray();

// und dann noch das
private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
    e.Graphics.DrawImage(pictureBox_Hintergrund.BackgroundImage, pictureBox_Hintergrund.Location.X, pictureBox_Hintergrund.Location.Y, pictureBox_Hintergrund.Width, pictureBox_Hintergrund.Height);
    for (int i = 0; i < boxen.Length; i++)
    {
        if (boxen[i].Name.Contains("new_"))
        {
            e.Graphics.DrawImage(boxen[i].BackgroundImage, boxen[i].Location.X, boxen[i].Location.Y, boxen[i].Width, boxen[i].Height);
        }
    }
}