ผมใช้ VC# 2008 กับ SQL SERVER 2008 ครับ เวลาที่ Insert ลง database ตอนรันบันทึกเรียบร้อยแต่พอมา รีเฟรช database มันก็กลับมาเหมือนเดิมคือมันไม่บันทึก

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;
using System.Data.SqlClient;

namespace Project
{
    public partial class Insertmain : Form
    {
        public Insertmain()
        {
            InitializeComponent();
        }
        private SqlConnection connection;
        private SqlCommand command;
        private string sql;

        private void Insertmain_Load(object sender, EventArgs e)
        {
            string conStr = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\DataPro.mdf;Integrated Security=True;User Instance=True;";
            connection = new SqlConnection(conStr);
            connection.Open();

            sql = "SELECT type_id as max FROM workunit_type";
            command = new SqlCommand(sql, connection);
            SqlDataAdapter adapter = new SqlDataAdapter(command);
            DataSet data = new DataSet();
            adapter.Fill(data, "ty");
            int numRow = data.Tables["ty"].Rows.Count;
            numRow = numRow + 1;
            string numRow2 = Convert.ToString(numRow);
            numRow2 = "wt0" + numRow2;
            textBox2.Text = numRow2;
        }

        private void textBox2_TextChanged(object sender, EventArgs e)
        {

        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();
            Workloadmain workmi = new Workloadmain();
            workmi.Show();
            connection.Close();

        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text != "")
            {

                sql = "insert into workunit_type values(@user,@pass)";
                //command = new SqlCommand(sql, connection);
                command.CommandText = sql;
                command.Parameters.AddWithValue("user", textBox2.Text);
                command.Parameters.AddWithValue("pass", textBox1.Text);
                int r = command.ExecuteNonQuery();
                if (r > 0)
                {
                    MessageBox.Show(textBox2.Text);
                    MessageBox.Show(textBox1.Text);
                    Close();
                    Workloadmain workmi = new Workloadmain();
                    workmi.Show();
                    connection.Close();
                 }
                else
                {
                    MessageBox.Show("เกิดความผิดพลาด กรุณาลองใหม่");
                    Close();
                }

            }

        }
    }
}