When it starts, the program uses the following code to display the available printers in a ComboBox.

// List the available printers.
private void Form1_Load(object sender, EventArgs e)
{
    foreach (string printer in PrinterSettings.InstalledPrinters)
    {
        cboPrinter.Items.Add(printer);
    }
}

This code loops through the System.Drawing.Printing.PrinterSettings.InstalledPrinters collection, adding each printer's name to the ComboBox.

When the user selects a printer and clicks the Print button, the following code sends the printout to the selected printer.

// Print.
private void btnPrint_Click(object sender, EventArgs e)
{
    // Select the printer.
    pdocSmiley.PrinterSettings.PrinterName = cboPrinter.Text;

    // Print.
    pdocSmiley.Print();
}

This code sets the PrintDocument's printer name to the selected printer's name and then calls the PrintDocument's Print method to generate the printout.