ADO.NET

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 TestApp
{
    public partial class Form1 : Form
    {
        SqlConnection connection;
        SqlCommand command;

        public Form1()
        {
            InitializeComponent();
        }

        private void buttonSearch_Click(object sender, EventArgs e)
        {
            StringBuilder str = new StringBuilder();
            SqlDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                str.Append(reader["Name"]);
                str.Append(reader["Surname"]);
                str.Append(reader["BirthDay"]);
            }
            MessageBox.Show(str.ToString());
            reader.Close();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            connection = new SqlConnection();
            connection.ConnectionString = "Server=LAB-418-11-PC\\STUDENT; database=Test_DB; Integrated Security=true;";
            connection.Open();
            MessageBox.Show(connection.State.ToString(), "State Of Connection");

            command = new SqlCommand();
            command.Connection = connection;
            command.CommandText = "SELECT * FROM Students WHERE Surname like '%" + textSearch.Text + "%'";
        }
    }
}