insert update delete find and fill textboxes c# 2010

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;//added for sqlserver database

namespace project_RETAIL

{

    public partial class Supplier : Form

    {

        public Supplier()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {//insert code

            string date = textBox1.Text.ToString();

            string supid = textBox2.Text.ToString();

            string supname = textBox3.Text.ToString();

            string supadd = textBox4.Text.ToString();

            string supcompany = textBox5.Text.ToString();

            string contactno = textBox6.Text.ToString();

            string connectionstring = @"Data Source=.\SQLEXPRESS;AttachDbFilename=e:\project-retail\dbRetail.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

            SqlConnection con = new SqlConnection(connectionstring);

            con.Open();

            SqlCommand cmd = new SqlCommand("insert into tblsupplier values(@date, @supid,@supname,@supadd,@supcompany,@supcontactno)", con);

            cmd.Parameters.AddWithValue("@date", date);

            cmd.Parameters.AddWithValue("@supid", supid);

            cmd.Parameters.AddWithValue("@supname", supname);

            cmd.Parameters.AddWithValue("@supadd", supadd);

            cmd.Parameters.AddWithValue("@supcompany", supcompany);

            cmd.Parameters.AddWithValue("@contactno",contactno);

            con.Close();

            MessageBox.Show("saved successfully");

        }

        private void button4_Click(object sender, EventArgs e)

        {//find and fill textboxes

            string date=textBox1.Text.ToString();

            string supid=textBox2.Text.ToString();

            string supname=textBox3.Text.ToString();

            string supadd=textBox4.Text.ToString();

            string supcompany=textBox5.Text.ToString();

            string contactno=textBox6.Text.ToString();

            string connectionstring = @"Data Source=.\SQLEXPRESS;AttachDbFilename=e:\project-retail\dbRetail.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

            SqlConnection con = new SqlConnection(connectionstring);

            SqlCommand cmd=new SqlCommand("select * from tblsupplier where supId='"+supid+"'",con);

                con.Open();

            SqlDataReader dr1=cmd.ExecuteReader();

            if(dr1.Read())

           

              {

              textBox1.Text=dr1.GetValue(0).ToString();

        textBox2.Text=dr1.GetValue(1).ToString();

        textBox3.Text=dr1.GetValue(2).ToString();

        textBox4.Text=dr1.GetValue(3).ToString();

        textBox5.Text=dr1.GetValue(4).ToString();

        textBox6.Text=dr1.GetValue(5).ToString();

               }

            con.Close();

         

        }

        private void button3_Click(object sender, EventArgs e)

        {//delete code

            string date=textBox1.Text.ToString();

            string supid=textBox2.Text.ToString();

            string supname=textBox3.Text.ToString();

            string supadd=textBox4.Text.ToString();

            string supcompany=textBox5.Text.ToString();

            string contactno=textBox6.Text.ToString();

            string connectionstring=@"Data Source=.\SQLEXPRESS;AttachDbFilename=e:\project-retail\dbRetail.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

            SqlConnection con=new SqlConnection(connectionstring);

            con.Open();

            SqlCommand cmd=new SqlCommand("delete from tblsupplier where supId='"+supid+"'",con);

            cmd.ExecuteNonQuery();

            con.Close();

            MessageBox.Show("Deleted successfully");

        }

        private void button2_Click(object sender, EventArgs e)

        {//update code

            string date = textBox1.Text.ToString();

            string supid = textBox2.Text.ToString();

            string supname = textBox3.Text.ToString();

            string supadd = textBox4.Text.ToString();

            string supcompany = textBox5.Text.ToString();

            string contactno = textBox6.Text.ToString();

            string connectionstring = @"Data Source=.\SQLEXPRESS;AttachDbFilename=e:\project-retail\dbRetail.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

            SqlConnection con = new SqlConnection(connectionstring);

            con.Open();

            SqlCommand cmd = new SqlCommand("update tblsupplier set supDate='" + date + "',supId='" + supid + "',supName='" + supname + "',supAddress='" + supadd + "',supCompany='" + supcompany + "',supContact='" + contactno + "'where supid='" + supid + "'", con);

            cmd.Parameters.AddWithValue("@supDate", date);

            cmd.Parameters.AddWithValue("@supId", supid);

            cmd.Parameters.AddWithValue("@supName", supname);

            cmd.Parameters.AddWithValue("@supAddress", supadd);

            cmd.Parameters.AddWithValue("@supCompany", supcompany);

            cmd.Parameters.AddWithValue("@Contactno", contactno);

            con.Close();

            MessageBox.Show("updates successfully");

        }

       

        }

        }