Code c#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SQLite;
namespace Sqlite_Demo
{
    public partial class Form1 : Form
    {
        SQLiteConnection _con = new SQLiteConnection();
        public void createConection()
        {
            string _strConnect = "Data Source=MyDatabase.sqlite;Version=3;";
            _con.ConnectionString = _strConnect;
            _con.Open();
        }

        public void closeConnection()
        {
            _con.Close();
        }

        public void createTable()
        {
            string sql = "CREATE TABLE IF NOT EXISTS tbl_students ([id] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, fullname nvarchar(50), birthday varchar(15), email varchar(30), address nvarchar(100), phone varchar(11))";
            SQLiteConnection.CreateFile("MyDatabase.sqlite");
            createConection();
            SQLiteCommand command = new SQLiteCommand(sql, _con);
            command.ExecuteNonQuery();
            closeConnection();
        }
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //createTable();
            loadDataToGrid();
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            txtID.Clear();
            txtFullname.Clear();
            txtBirthday.Clear();
            txtEmail.Clear();
            txtAddress.Clear();
            txtPhone.Clear();
            txtFullname.Focus();
        }
        public  DataSet loadData()
        {
            DataSet ds = new DataSet();
            createConection();
            SQLiteDataAdapter da = new SQLiteDataAdapter("select id, fullname as [Full Name], email as [Email], address as [Address], phone as [Phone], birthday as [Birthday] from tbl_students", _con);

            da.Fill(ds);
            closeConnection();
            return ds;
        }

        public void loadDataToGrid()
        {
            DataSet ds = loadData();
            gvDataStudent.DataSource = ds.Tables[0];
            txtID.DataBindings.Clear();
            txtFullname.DataBindings.Clear();
            txtBirthday.DataBindings.Clear();
            txtEmail.DataBindings.Clear();
            txtAddress.DataBindings.Clear();
            txtPhone.DataBindings.Clear();
            txtID.DataBindings.Add("text", ds.Tables[0], "id");
            txtFullname.DataBindings.Add("text", ds.Tables[0], "Full name");
            txtBirthday.DataBindings.Add("text", ds.Tables[0], "Birthday");
            txtEmail.DataBindings.Add("text", ds.Tables[0], "Email");
            txtAddress.DataBindings.Add("text", ds.Tables[0], "Address");
            txtPhone.DataBindings.Add("text", ds.Tables[0], "Phone");

            txtSoDong.Text = "Tổng số dòng: ";
            txtDongboiden.Text = "Số dòng đang bôi đen: ";

        }
        private void btnSave_Click(object sender, EventArgs e)
        {
            string fullname = txtFullname.Text;
            string birthday = txtBirthday.Text;
            string email = txtEmail.Text;
            string address = txtAddress.Text;
            string phone = txtPhone.Text;

            string strInsert = string.Format("INSERT INTO tbl_students(fullname, birthday, email, address, phone) VALUES('{0}','{1}','{2}','{3}','{4}')", fullname, birthday, email, address, phone);

            createConection();
            SQLiteCommand cmd = new SQLiteCommand(strInsert, _con);
            cmd.ExecuteNonQuery();
            closeConnection();

            // load data
            loadDataToGrid();
        }

        private void btnUpdate_Click(object sender, EventArgs e)
        {
            string id = txtID.Text;
            string fullname = txtFullname.Text;          
            string birthday = txtBirthday.Text;
            string email = txtEmail.Text;
            string address = txtAddress.Text;
            string phone = txtPhone.Text;

            string strInsert = string.Format("UPDATE tbl_students set fullname='{0}', birthday='{1}', email='{2}', address='{3}', phone='{4}' where id='{5}'", fullname, birthday, email, address, phone, id);

            createConection();
            SQLiteCommand cmd = new SQLiteCommand(strInsert, _con);
            cmd.ExecuteNonQuery();
            closeConnection();

            // load data
            loadDataToGrid();
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            string id = txtID.Text;           

            string strInsert = string.Format("DELETE FROM tbl_students where id='{0}'", id);

            createConection();
            SQLiteCommand cmd = new SQLiteCommand(strInsert, _con);
            cmd.ExecuteNonQuery();
            closeConnection();

            // load data
            loadDataToGrid();
        }
        private void gvDataStudent_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            //if (MetaData.Rows[e.RowIndex].Cells[e.ColumnIndex].Value != null)
            //{
            gvDataStudent.CurrentRow.Selected = true;
            // txtID.Text = MetaData.Rows[e.RowIndex].Cells[0].Value.ToString();
            // txtFullname.Text = MetaData.Rows[e.RowIndex].Cells[1].Value.ToString();
            // txtEmail.Text = MetaData.Rows[e.RowIndex].Cells[2].Value.ToString();
            //txtAddress.Text = MetaData.Rows[e.RowIndex].Cells[3].Value.ToString();
            //txtPhone.Text = MetaData.Rows[e.RowIndex].Cells[4].Value.ToString();
            //txtBirthday.Text = MetaData.Rows[e.RowIndex].Cells[5].Value.ToString();
            //MessageBox.Show("Selected row is=" + e.RowIndex);
            Int32 selectedRowCount =
            gvDataStudent.Rows.GetRowCount(DataGridViewElementStates.Selected);
            if (selectedRowCount > 0)
            {
                System.Text.StringBuilder sb = new System.Text.StringBuilder();
                for (int i = 0; i < selectedRowCount; i++)
                {
                    // sb.Append("Row: ");
                    sb.Append(gvDataStudent.SelectedRows[i].Index.ToString());
                    sb.Append(Environment.NewLine);
                }
                sb.Append("Total: " + selectedRowCount.ToString());
                txtDongboiden.Text = "Số dòng đang bôi đen: " + selectedRowCount.ToString();
                //MessageBox.Show(sb.ToString(), "Selected Rows");
            }



            // }
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }
}