TestEdDatabaseEntities _context;

        IDbTransaction _transaction;

        public Form1()
        {
            InitializeComponent();
            _context = new TestEdDatabaseEntities();
        }

        private void OpenTransaction_Click(object sender, EventArgs e)
        {
            if (this._transaction == null)
            {
                if (_context.Connection.State == ConnectionState.Closed)
                {
                    _context.Connection.Open();
                }
                _transaction = _context.Connection.BeginTransaction(IsolationLevel.ReadCommitted);
            }

        }

        private void ChangeData_Click(object sender, EventArgs e)
        {
            if (_transaction != null)
            {
                Random r = new Random();
                foreach (var item in _context.Table1Set)
                {
                    item.SearctField1 = r.Next();
                }
                _context.SaveChanges();
            }
        }

        private void CloseTransaction_Click(object sender, EventArgs e)
        {
            if (_transaction != null)
            {
                _transaction.Commit();
                _context.Connection.Close();
                _transaction = null;
            }
        }