private void button5_Click(object sender, EventArgs e)
        {
            FormVolunteers fm = new FormVolunteers(email);

            fm.Show();
            this.Hide();
        }
        private void button3_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection(Connection.GetString());

            conn.Open();
            string[] data = File.ReadAllLines(openFileDialog1.FileName);

            for (int i = 1; i < data.Length; i++)
            {
                String[] word = data[i].Split(new char[] { ',' });

                for (int j = 0; j < word.Length; j++)
                {
                    //MessageBox.Show(word[j]);
                    SqlCommand commanSearchId = new SqlCommand("SELECT * FROM Volunteer WHERE VolunteerId = '" + word[0] + "'", conn);
                    bool       t = true;
                    using (SqlDataReader reader = commanSearchId.ExecuteReader())
                    {
                        if (reader.HasRows)
                        {
                            t = false;
                        }
                    }

                    if (!t)
                    {
                        try
                        {
                            if (word[4] == "F")
                            {
                                word[4] = "Female";
                            }
                            if (word[4] == "M")
                            {
                                word[4] = "Male";
                            }

                            SqlCommand command1 = new SqlCommand("UPDATE Volunteer Set FirstName = '" + word[2] + "', LastName = '" + word[1] + "', CountryCode = '" + word[3] + "', Gender = '" + word[4] + "' WHERE VolunteerId = '" + word[0] + "'", conn);
                            command1.ExecuteNonQuery();
                        }
                        catch (Exception ex)
                        {
                        }
                    }


                    if (t)
                    {
                        try
                        {
                            SqlCommand insert = new SqlCommand("SET IDENTITY_INSERT Volunteer ON", conn);
                            insert.ExecuteNonQuery();
                            SqlCommand command2 = new SqlCommand("SET IDENTITY_INSERT Volunteer ON; INSERT INTO Volunteer(VolunteerId, FirstName, LastName, CountryCode, Gender) Values(@id, @f, @l, @c, @g)", conn);

                            if (word[4] == "F")
                            {
                                word[4] = "Female";
                            }
                            if (word[4] == "M")
                            {
                                word[4] = "Male";
                            }

                            command2.Parameters.Add("@id", word[0]);
                            command2.Parameters.Add("@f", word[2]);
                            command2.Parameters.Add("@l", word[1]);
                            command2.Parameters.Add("@c", word[3]);
                            command2.Parameters.Add("@g", word[4]);

                            command2.ExecuteNonQuery();
                        }
                        catch (Exception ex)
                        {
                        }
                    }
                }
            }

            MessageBox.Show("Данные о волонтерах успешно добавлены!", "Оповещение системы");
            FormVolunteers fm = new FormVolunteers(email);

            fm.Show();
            this.Hide();
        }