C# winApp printDocument PrintPage สั่งปริ้นแล้วมีข้อความที่ทับกันอยู่ ครับ

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Printing;
using System.IO;
using System.Linq;

using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace KidsLearning.Print
{
    public partial class prnControl : UserControl
    {
        public prnControl()
        {
            InitializeComponent();
        }
        #region Variables

       
        protected string ReportHeader;
        protected string ReportToppic;

        protected Font fontHeader = new Font("CordiaUPC", 18, FontStyle.Bold);
        protected Font fontDetail = new Font("CordiaUPC", 18);
        protected Font fontExpression = new Font("Microsoft Sans Serif", 18);

        public string filePrintPre = "";

        protected System.Drawing.StringFormat strFormat = new StringFormat()
        {
            Alignment = StringAlignment.Near,
            LineAlignment = StringAlignment.Center,
            Trimming = StringTrimming.EllipsisCharacter
        }; //Used to format the grid rows.

        protected int iPage = 1;
        protected int iPageAll = 10;
        protected bool bFirstPage = false; //Used to check whether we are printing first page
        protected bool bNewPage = false;// Used to check whether we are printing a new page
        //Whether more pages have to print or not
        protected bool bMorePagesToPrint = false;
      

        #endregion
        private void printDocument1_BeginPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
        {
            Cursor.Current = Cursors.WaitCursor;
            bFirstPage = true;
            bNewPage = true;
        }

        private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
        {

        }
       internal void printDocumentNewPage(object sender, PrintPageEventArgs e)
        {
            // System.Windows.Forms.MessageBox.Show(_ReportHeader);
            //Draw Header
            //  string strToppic = "แปลงหน่วยนับ ต่อไปนี้ให้ถูกต้อง";
            e.Graphics.DrawString(ReportHeader, fontHeader, Brushes.Black, 300, e.MarginBounds.Top - e.Graphics.MeasureString(ReportHeader, fontHeader, e.MarginBounds.Width).Height - 13);
            e.Graphics.DrawString(ReportToppic, fontHeader, Brushes.Black, 100, 90);
            //Draw Footer
            e.Graphics.DrawString($"test date ...../...../.......  by.......................  Print date {DateTime.Now.ToString("yyyyMMdd hhmmss")}  Page{iPage}/{iPageAll}", fontDetail, Brushes.Black, e.MarginBounds.Left -40, e.MarginBounds.Bottom + 40);

        }
        private void prnControl_Load(object sender, EventArgs e)
        {
            this.Dock = DockStyle.Fill;
            this.printDocument1.DefaultPageSettings.Landscape = false;
          //  groupBox1.Width = 250;
        }

        private void bntPrint_Click(object sender, EventArgs e)
        {
            if (System.Windows.Forms.DialogResult.OK == this.printDialog1.ShowDialog())
            {
                string filePre = Application.StartupPath +  filePrintPre;
               
               /* if ( File.Exists(filePre))
                {
                    if (MessageBox.Show("คุณต้องการสั่งปริ้น เนื้อหา/บทเรียน ด้วยหรือไม่", "แจ้งเตือน", MessageBoxButtons.YesNo) == DialogResult.Yes)
                    {
                        TORServices.Drawings.PrintFile.Print(filePre);
                    }
                    
                }*/
                bNewPage = true;
                bMorePagesToPrint = true;

                iPageAll = int.Parse(this.txtPageCount.Text);
                iPage = 1;
                this.printDocument1.PrinterSettings.PrinterName = printDialog1.PrinterSettings.PrinterName;
                this.printDocument1.DocumentName = ReportHeader + string.Format("{0:yyyyMMdd hhmmss}", DateTime.Now);
                this.printDocument1.Print();
            }
        }
        


        private void printDocument1_EndPrint(object sender, PrintEventArgs e)
        {
            Cursor.Current = Cursors.Default;
        }
    }
}

private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
        {
            //Loop till all the grid rows not get printed
            if (bFirstPage) printDocumentNewPage(sender, e);

            #region _Draw Detail

            int yC = 120, xC = 100;
            int a = 0, b = 0, _a = 0, _b = 0,
                den_1 = 1, den_2 = 1, _den_1 = 1, _den_2 = 1,
                ext_1 = 0, ext_2 = 0, _ext_1 = 0, _ext_2 = 0;
            string _sop = Sop;
            string _Den;
            for (int i = 0; i < 6; i++)
            {

                _den_1 = 1;
                _den_2 = 1;
                _ext_1 = 0;
                _ext_2 = 0;
                if (Den == "E/NE")
                {
                    switch (RandomNumber.Randomnumber(1, 4000))
                    {
                        case int n when n > 3000:
                            _Den = "E"; break;
                        case int n when n <= 3000 && n > 2000:
                            _Den = "NE"; break;
                        case int n when n <= 2000 && n > 1000:
                            _Den = "E_Int"; break;
                        case int n when n <= 1000:
                            _Den = "E_Flc"; break;
                        default:
                            _Den = "E"; break;
                    }
                }
                else
                {
                    _Den = Den;
                }

                if (_Den == "E")//ส่วนเหมือนกัน
                {
                    _den_1 = RandomNumber.Randomnumber(3, 10);
                    _den_2 = _den_1;

                }
                else if (_Den == "NE")//ส่วนต่างกัน
                {
                    _den_1 = RandomNumber.Randomnumber(4, 10);
                    do
                    {
                        _den_2 = RandomNumber.Randomnumber(2, 10);
                    } while (_den_1 == _den_2);

                }
                else if (_Den == "E_Int")//แบบมีจำนวนเต็ม
                {
                    int aa = RandomNumber.Randomnumber(1, 3000);
                    if (aa > 1500)
                    {
                        _den_2 = 1;
                        _den_1 = RandomNumber.Randomnumber(3, 10);
                    }
                    else
                    {
                        _den_1 = 1;
                        _den_2 = RandomNumber.Randomnumber(3, 10);
                    }

                    //  MessageBox.Show(_den_1 + "  " + _den_2);
                }
                else if (_Den == "E_Flc")//แบบมีจำนวนคละ
                {

                    _den_1 = RandomNumber.Randomnumber(5, 10);
                    _den_2 = RandomNumber.Randomnumber(5, 10);
                    _ext_1 = RandomNumber.Randomnumber(0, 10);
                    _ext_2 = RandomNumber.Randomnumber(0, 10);
                    /*int aa = RandomNumber.Randomnumber(1, 3000) ;
                    if (aa > 2000)
                    {
                        _ext_1 = RandomNumber.Randomnumber(1, 10);
                        
                    }
                    else if (aa < 1000)
                    {
                  
                        _ext_2 = RandomNumber.Randomnumber(1, 10);
                    }
                    else
                    {
                        _ext_1 = RandomNumber.Randomnumber(1, 10);
                        _ext_2 = RandomNumber.Randomnumber(1, 10);
                    }*/


                }


                // MessageBox.Show(_sop + "  " + Den);

                //ถ้าเป็นจำนวนเต็ม _den จะ เท่ากับ 1

                _a = (_den_1 == 1) ? RandomNumber.Randomnumber(1, 10) :
                ((_den_1 == 2) ? 1 : RandomNumber.Randomnumber(1, _den_1));
                _b = (_den_2 == 1) ? RandomNumber.Randomnumber(1, 10) :
                    ((_den_2 == 2) ? 1 : RandomNumber.Randomnumber(1, _den_2));

                a = _a;
                b = _b;
                den_1 = _den_1;
                den_2 = _den_2;
                ext_1 = _ext_1;
                ext_2 = _ext_2;

                if (Sop == "+-x÷")
                {

                    int aa = RandomNumber.Randomnumber(1, 4000);
                    switch (aa)
                    {
                        case int n when n > 3000:
                            _sop = "+";
                            break;
                        case int n when n <= 3000 && n > 2000:
                            _sop = "-";
                            break;
                        case int n when n <= 2000 && n > 1000:
                            _sop = "x";
                            break;
                        case int n when n <= 1000:
                            _sop = "÷";
                            break;
                        default:
                            _sop = "+";
                            break;

                    }
                }

                if (_sop == "-")
                {
                    double v_a = (Convert.ToDouble(((_ext_1 == 0) ? 1d : _ext_1)) * Convert.ToDouble(_den_1) + Convert.ToDouble(_a)) / Convert.ToDouble(_den_1);
                    double v_b = (Convert.ToDouble(((_ext_2 == 0) ? 1d : _ext_2)) * Convert.ToDouble(_den_2) + Convert.ToDouble(_b)) / Convert.ToDouble(_den_2);
                    //  MessageBox.Show($"{_a} + {_den_1}*{_ext_1} = {v_a}"  + "\n" + $"{_b} + {_den_2}*{_ext_2} = {v_b}" );
                    if (v_a > v_b)
                    {
                        a = _b;
                        b = _a;
                        den_1 = _den_2;
                        den_2 = _den_1;
                        ext_1 = _ext_2;
                        ext_2 = _ext_1;
                    }
                    else if (v_a == v_b)
                    {
                        b += (b == 1) ? 1 : RandomNumber.Randomnumber(1, b);
                    }

                }




                if (den_2 > 1)
                {
                    e.Graphics.DrawFraction(ext_2, b, den_2, xC + 10, yC);
                }
                else
                {
                    e.Graphics.DrawString(b.ToString(), new Font("Angsana New", 22), new SolidBrush(Color.Black), xC + 60, yC + 15);
                }

                e.Graphics.DrawString(_sop, new Font("Angsana New", 22), new SolidBrush(Color.Black), xC + 80, yC + 15);

                if (den_1 > 1)
                {
                    e.Graphics.DrawFraction(ext_1, a, den_1, xC + 100, yC);
                }
                else
                {
                    e.Graphics.DrawString(b.ToString(), new Font("Angsana New", 22), new SolidBrush(Color.Black), xC + 110, yC + 15);
                }


                e.Graphics.DrawString(" วิธีทำ# ", new Font("Angsana New", 20), new SolidBrush(Color.Black), xC + 200, yC + 5);
                yC += 150;

            }


            #endregion



            if (iPage > iPageAll - 1)
            {
                bNewPage = false;
                bMorePagesToPrint = false;
            }

            if (bNewPage)
            {
                printDocumentNewPage(sender, e);
            }

            iPage++;

            //If more lines exist, print another page.
            e.HasMorePages = (bMorePagesToPrint) ? true : false;
        }

e.Graphics.DrawString($"test date ...../...../.......  by.......................  Print date {DateTime.Now.ToString("yyyyMMdd hhmmss")}  Page{iPage}/{iPageAll}", fontDetail, Brushes.Black, e.MarginBounds.Left -40, e.MarginBounds.Bottom + 40);