GUI Windows Form C#

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Printing;
public class frmMain : System.Windows.Forms.Form {
    private System.Drawing.Printing.PrintDocument printDoc;
    private System.Windows.Forms.PrintPreviewDialog ppDialog;
    private System.Windows.Forms.Button btnPrint;
    public frmMain() {
        this.printDoc = new System.Drawing.Printing.PrintDocument();
        this.ppDialog = new System.Windows.Forms.PrintPreviewDialog();
        this.btnPrint = new System.Windows.Forms.Button();
        this.SuspendLayout();
        this.printDoc.PrintPage += new System.Drawing.Printing.PrintPageEventHandler(this.printDoc_PrintPage);
        this.ppDialog.AutoScrollMargin = new System.Drawing.Size(0, 0);
        this.ppDialog.AutoScrollMinSize = new System.Drawing.Size(0, 0);
        this.ppDialog.ClientSize = new System.Drawing.Size(400, 300);
        this.ppDialog.Enabled = true;
        this.ppDialog.Location = new System.Drawing.Point(195, 22);
        this.ppDialog.MaximumSize = new System.Drawing.Size(0, 0);
        this.ppDialog.Opacity = 1;
        this.ppDialog.TransparencyKey = System.Drawing.Color.Empty;
        this.ppDialog.Visible = false;
        this.btnPrint.Location = new System.Drawing.Point(52, 28);
        this.btnPrint.Text = "Print";
        this.btnPrint.Click += new System.EventHandler(this.btnPrint_Click);
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
        this.ClientSize = new System.Drawing.Size(176, 86);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                      this.btnPrint});
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
        this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
        this.ResumeLayout(false);
    }
    [STAThread]
    static void Main() {
        Application.Run(new frmMain());
    }
    private void printDoc_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e) {
        PrinterSettings pSettings = new PrinterSettings();
        Font printFont = new Font("Arial", 12);
        int nTextPosY = e.MarginBounds.Top;
        int nTextPosX = e.MarginBounds.Left;
        int nHeight = (int)printFont.GetHeight(e.Graphics);
        foreach (string sPtr in PrinterSettings.InstalledPrinters) {
            pSettings.PrinterName = sPtr;
            if (pSettings.IsValid) {
                e.Graphics.DrawString(sPtr, printFont, Brushes.Black, nTextPosX, nTextPosY + 5);
                e.Graphics.DrawString("Can Duplex: " + pSettings.CanDuplex.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight));
                e.Graphics.DrawString("Is Default: " + pSettings.IsDefaultPrinter.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 2));
                e.Graphics.DrawString("Is Plotter: " + pSettings.IsPlotter.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 3));
                e.Graphics.DrawString("Landscape Angle: " + pSettings.LandscapeAngle.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 4));
                e.Graphics.DrawString("Maximum Copies: " + pSettings.MaximumCopies.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 5));
                e.Graphics.DrawString("Maximum Page: " + pSettings.MaximumPage.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 6));
                e.Graphics.DrawString("Minimum Page: " + pSettings.MinimumPage.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 7));
                e.Graphics.DrawString("Supports Color: " + pSettings.SupportsColor.ToString(),
                    printFont, Brushes.Black, nTextPosX + 10, nTextPosY + (5 + nHeight * 8));
                nTextPosY = nTextPosY + ((5 + nHeight * 8) + nHeight);
            }
        }
    }
    private void btnPrint_Click(object sender, System.EventArgs e) {
        ppDialog.Document = printDoc;
        ppDialog.ShowDialog();
    }
}