Find the data of the column in SQL database on the basis of one column

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 WindowsFormsApplication16

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        SqlDataAdapter da;

        DataSet ds;

        private void Form1_Load(object sender, EventArgs e)

        {

            da = new SqlDataAdapter("select * from emp", "data source=MKS-PC\\SQLEXPRESS;Initial Catalog=master;integrated security=true");

            ds = new DataSet();

            da.Fill(ds);

        }

        private void button1_Click(object sender, EventArgs e)

        {

            bool b = false;

            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)

            {

                if (ds.Tables[0].Rows[i][0].ToString().Trim() == textBox1.Text.Trim())

                {

                    textBox2.Text = ds.Tables[0].Rows[i][1].ToString();

                    textBox3.Text = ds.Tables[0].Rows[i][2].ToString();

                    b = true;

                    break;

                }

            }

            if (!b)

            {

                MessageBox.Show("Id does not exist");

            }

        }

    }

}