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richTextBox1.Text += string.Format("({0}, {1})\n", a.ToString(), b.ToString());					

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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using Line2D;
using System.Collections;

namespace WindowsFormsApplication1
{
    public partial class KonturGraph : Form
    {
        public KonturGraph()
        {
            InitializeComponent();

            Line2D.Line2D line2d = new Line2D.Line2D();

            line2d.Height = 500;
            line2d.Width = 700;
            line2d.XSlice = 50;
            line2d.YSlice = 10;
            line2d.XAxisText = "X";
            line2d.YAxisText = "Y";
            line2d.Title = "Messung";
            line2d.TitleBackColor = Color.Linen;
            line2d.TitleForeColor = Color.Red;

            line2d.InitializeGraph();

            ArrayList arX = new ArrayList();
            ArrayList arY = new ArrayList();

            arX = new ArrayList();
            arY = new ArrayList();
            arX.Add(50); arX.Add(33.444); arX.Add(33.48); // X-Werte
            arY.Add(10); arY.Add(10.09); arY.Add(10.09);  //Y- Werte
            line2d.XAxis = arX;
            line2d.YAxis = arY;
            line2d.CreateGraph(Color.Blue);

            Bitmap bmp = line2d.GetGraph();
            pictureBox1.Image = bmp;
        }

        private void pictureBox1_Click( object sender, EventArgs e )
        {

        }
    }
}