99/10/1作業修改後

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        Form2 newform;
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            int a1, an, d, n, sum;
            a1 = int.Parse(textBox1.Text);
            d = int.Parse(textBox2.Text);
            n = int.Parse(textBox3.Text);
            an = a1 + (n - 1) * d;
            sum = (a1 + an) * n / 2;
            textBox4.Text = "" + an;
            textBox5.Text = "" + sum;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
        }
        private void label2_Click(object sender, EventArgs e)
        {
        }
        private void button2_Click(object sender, EventArgs e)
        {
        }
        private void button2_Click_1(object sender, EventArgs e)
        {
            newform = new Form2();
            newform.Show();
        }
    }
}

第二表單
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            int s;
            int[,] arr1 = new int[101, 101];
            for (int i = 1; i <= 9; i++)
            {
                for (int j = 1; j <= 9; j++)
                {
                    s = i * j;
                    arr1[i, j] = s;
                    listBox1.Items.Add("" + i + "*" + "" + j + "=" + arr1[i, j]);
                }
            }
        }
        private void button2_Click_1(object sender, EventArgs e)
        {
            int s;
            int[,] arr1 = new int[101, 101];
            for (int i = 1; i <= 9; i++)
            {
                for (int j = 1; j <= 9; j++)
                {
                    s = i * j;
                    arr1[i, j] = s;
                    listBox1.Items.Add("" + i + "*" + "" + j + "=" + arr1[i, j]);
                }
            }
        }
    }
}













int[,] arr = new int[10, 10];
            int sum = 0;
            for (int j = 0; j < 9; j++)
                for (int k = 0; k < 9; k++)
                {
                    arr[j, k] = (j + 1) * (k + 1);
                    sum = arr[j, k];
                    //listBox1.Items.Add("arr[" + (j + 1) + "]" + "[" + (k + 1) + "]=" + sum);
                }
            for (int j = 0; j < 9; j++)
            {
                listBox1.Items.Add("" + arr[j, 0] + "," + arr[j, 1] + "," + arr[j, 2] + "," + arr[j, 3] + "," + arr[j, 4] + "," + arr[j, 5] + "," + arr[j, 6] + "," + arr[j, 7] + "," + arr[j, 8]);

            }