จากรูป เป็น รูปแบบ controlchart  ครับ
โดยผมอยากรับข้อมูลมาชุดหนึ่ง จากนั้น สร้างกราฟ แยกในแต่ละหน้า
เลื่อนหน้าโดยการ กดปุ่ม ซ้ายขวา ด้านบน ครับ
ตอนนี้ ติด ปัญหา ดังนี้ครับ

1. ผมจะแยก แต่ละหน้าได้อย่างไร เริ่มต้น ผมคิดไว้ว่าจะแยก ทีละ 30 ข้อมูล ก่อน โดยความห่างของข้อมูลในแกนนอน  เป็น 50
[Spoil] คลิกเพื่อดูข้อความที่ซ่อนไว้ int SizeColumn = 50;
แต่คิดไม่ออก ว่า จะแยกเป้นหน้าๆ ยังไง เพราะ
2. ถ้ามีการ ย่อขยายความห่างของข้อมูลในแกนนอน  ยังเป็น 50 อยู่ แสดงว่า จำนวนข้อมูลแต่ละหน้า ก็ต้องเปลี่ยนไป

โค้ดครับ
[Spoil] คลิกเพื่อดูข้อความที่ซ่อนไว้using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using TORServices.DB.PrintDB;
namespace TORServices.Forms
{
        public partial class controlChart : UserControl
    {
        /// <summary> 
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;
        /// <summary> 
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }
        #region Component Designer generated code
        /// <summary> 
        /// Required method for Designer support - do not modify 
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.panel1 = new System.Windows.Forms.Panel();
            this.btnNext = new System.Windows.Forms.Button();
            this.btnPrevious = new System.Windows.Forms.Button();
            this.lblPage = new System.Windows.Forms.Label();
            this.panel1.SuspendLayout();
            this.SuspendLayout();
            // 
            // panel1
            // 
            this.panel1.Controls.Add(this.lblPage);
            this.panel1.Controls.Add(this.btnNext);
            this.panel1.Controls.Add(this.btnPrevious);
            this.panel1.Dock = System.Windows.Forms.DockStyle.Top;
            this.panel1.Location = new System.Drawing.Point(0, 0);
            this.panel1.Name = "panel1";
            this.panel1.Size = new System.Drawing.Size(1010, 51);
            this.panel1.TabIndex = 0;
            // 
            // btnNext
            // 
            this.btnNext.BackgroundImage = global::TORServices.Forms.Properties.Resources.arrow_next_right;
            this.btnNext.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Zoom;
            this.btnNext.Dock = System.Windows.Forms.DockStyle.Right;
            this.btnNext.Location = new System.Drawing.Point(960, 0);
            this.btnNext.Name = "btnNext";
            this.btnNext.Size = new System.Drawing.Size(50, 51);
            this.btnNext.TabIndex = 2;
            this.btnNext.UseVisualStyleBackColor = true;
            this.btnNext.Click += new System.EventHandler(this.btnNext_Click);
            // 
            // btnPrevious
            // 
            this.btnPrevious.BackgroundImage = global::TORServices.Forms.Properties.Resources.arrow_left_previous;
            this.btnPrevious.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Zoom;
            this.btnPrevious.Dock = System.Windows.Forms.DockStyle.Left;
            this.btnPrevious.Location = new System.Drawing.Point(0, 0);
            this.btnPrevious.Name = "btnPrevious";
            this.btnPrevious.Size = new System.Drawing.Size(50, 51);
            this.btnPrevious.TabIndex = 0;
            this.btnPrevious.UseVisualStyleBackColor = true;
            this.btnPrevious.Click += new System.EventHandler(this.btnPrevious_Click);
            // 
            // lblPage
            // 
            this.lblPage.Dock = System.Windows.Forms.DockStyle.Bottom;
            this.lblPage.Font = new System.Drawing.Font("Microsoft Sans Serif", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.lblPage.ForeColor = System.Drawing.Color.White;
            this.lblPage.Location = new System.Drawing.Point(50, 27);
            this.lblPage.Name = "lblPage";
            this.lblPage.Size = new System.Drawing.Size(910, 24);
            this.lblPage.TabIndex = 3;
            this.lblPage.Text = "Page";
            this.lblPage.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
            // 
            // controlChart
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.BackColor = System.Drawing.Color.Black;
            this.Controls.Add(this.panel1);
            this.Name = "controlChart";
            this.Size = new System.Drawing.Size(1010, 551);
            this.Resize += new System.EventHandler(this.controlChart_Resize);
            this.panel1.ResumeLayout(false);
            this.ResumeLayout(false);
        }
        #endregion

        public controlChart()
        {
            InitializeComponent();
        }
        public double ValueMean, ValueSD;
        public  int Decimal = 4;
        private Panel panel1;
        private Button btnNext;
        private Button btnPrevious;
        public List<DataControlChart> Datas;
        int contPerPage = 30;
        int page = 1;
        int Allpage = 1;
        private Label lblPage;
        int item = 0;
        int startItem = 0;
        int SizeColumn = 50;
        public void RefreshChart(int pg = 1)
        {
            if (Datas == null || Datas.Count < 1) return;
            // Set value 
            double vUp3SD = ValueMean + (3 * ValueSD);
            double vUp2SD = ValueMean + (2 * ValueSD);
            double vDwn2SD = ValueMean - (2 * ValueSD);
            double vDwn3SD = ValueMean - (3 * ValueSD);
            int lntMain = Convert.ToInt32(this.Height / 2);
            int lntUp3SD = lntMain - Convert.ToInt32(lntMain / 1.2);
            int lntUp2SD = lntMain - Convert.ToInt32(lntMain / 2);
            int lntDwn2SD = lntMain + Convert.ToInt32(lntMain / 2);
            int lntDwn3SD = lntMain + Convert.ToInt32(lntMain / 1.2);
            double ddd = (lntDwn3SD - lntUp3SD) / (vUp3SD - vDwn3SD);
            Bitmap b = new Bitmap(this.Width, this.Height);
            int _x1 = 120;
            btnNext.Visible = false;
            btnPrevious.Visible = false;
            using (Graphics g = Graphics.FromImage(b))
            {
                g.Clear(Color.Black);
                g.FillRectangle(Brushes.Black, new Rectangle(0, 0, b.Width, b.Height));
                System.Drawing.Pen p;
                g.DrawString("     Main--" + ValueMean.ToString("N" + Decimal), this.Font, Brushes.Azure, 5, lntMain - 5);
                g.DrawString(" Main - 2SD--" + vDwn2SD.ToString("N" + Decimal), this.Font, Brushes.Azure, 5, lntDwn2SD - 5);
                g.DrawString(" Main + 2SD--" + vUp2SD.ToString("N" + Decimal), this.Font, Brushes.Azure, 5, lntUp2SD - 5);
                g.DrawString("  Main -3SD--" + vDwn3SD.ToString("N" + Decimal), this.Font, Brushes.Azure, 5, lntDwn3SD - 5);
                g.DrawString(" Main + 3SD--" + vUp3SD.ToString("N" + Decimal), this.Font, Brushes.Azure, 5, lntUp3SD - 5);

                g.DrawLine(new System.Drawing.Pen(Brushes.Pink, 3), _x1, lntMain, b.Width, lntMain);
                g.DrawLine(new System.Drawing.Pen(Brushes.Yellow, 2), _x1, lntDwn2SD, b.Width, lntDwn2SD);
                g.DrawLine(new System.Drawing.Pen(Brushes.Yellow, 2), _x1, lntUp2SD, b.Width, lntUp2SD);
                g.DrawLine(new System.Drawing.Pen(Brushes.Red, 2), _x1, lntDwn3SD, b.Width, lntDwn3SD);
                g.DrawLine(new System.Drawing.Pen(Brushes.Red, 2), _x1, lntUp3SD, b.Width, lntUp3SD);
                int x1 = _x1 + 10;
                int y1 = 0;
                int x2 = 0;
                int y2 = 0;
                x2 = x1 + SizeColumn + Convert.ToInt32(SizeColumn / 2.2);
                y1 = (int)((ddd * (vUp3SD - (double)Datas[0]._value)) + lntUp3SD);
                g.DrawString(((double)Datas[0]._value).ToString("N" + Decimal) + Environment.NewLine +
                                   Datas[0]._date.ToString("dd/MM/yyyy"),
                                   this.Font, Brushes.White, x1 + 5, y1);
                y2 = 0;
                p = new System.Drawing.Pen(Brushes.Blue, 5);
                p.EndCap = System.Drawing.Drawing2D.LineCap.RoundAnchor;
                p.StartCap = System.Drawing.Drawing2D.LineCap.RoundAnchor;

                for (int i = 1; i <= contPerPage; i++)
                {
                    
                    if (i > 0) x2 = x2 + SizeColumn;
                    if (!string.IsNullOrEmpty("" + Datas[item]._value))
                    {
                        y2 = (int)((ddd * (vUp3SD - (double)Datas[item]._value)) + lntUp3SD);
                        g.DrawLine(p, x1, y1, x2, y2);
                        g.DrawString(((double)Datas[item]._value).ToString("N" + Decimal) + Environment.NewLine +
                            Datas[item]._date.ToString("dd/MM/yyyy"),
                            this.Font, Brushes.White, x2 + 5, y2);
                        x1 = x2;
                        y1 = y2;
                    }
                    item++;
                    if (item >= Datas.Count) break;
                }
                
              /*  if(item < Datas.Count)
                    btnNext.Visible = true;
                else
                    btnNext.Visible = false*/
                 btnNext.Visible = (item < Datas.Count) ;
                btnPrevious.Visible = (item > contPerPage);
               /* if (item > contPerPage)
                {
                    btnPre