private void button1_Click(object sender, EventArgs e)
        {
            if (textBox_login.Text == "")
                MessageBox.Show("Por favor, insira um login");
            else if (textBox_password.Text == "")
                MessageBox.Show("Por favor, insira uma senha");

            else if (comboBox_type.Text == "Administrador")
            {
                SqlConnection con = new SqlConnection("Integrated Security=SSPI;Persist Security Info=False;User ID=DESKTOP-PI7D0K7\\SQLEXPRESS;Initial Catalog=trabalho_tp1_kaio_bruno;Data Source=DESKTOP-PI7D0K7\\SQLEXPRESS");
                SqlCommand cmd = new SqlCommand("select id, nome from admin where login=@login and senha=@senha", con);
                cmd.Parameters.Add("@login", SqlDbType.VarChar).Value = textBox_login.Text;
                cmd.Parameters.Add("@senha", SqlDbType.VarChar).Value = textBox_password.Text;

                try
                {
                    con.Open();
                    SqlDataReader dr = cmd.ExecuteReader();
                    if (dr.HasRows == false)
                    {
                        throw new Exception("Usuario Nao encontrado");
                    }

                        dr.Read();

                        string nome;
                        nome = Convert.ToString(dr["nome"]);

                        MessageBox.Show("Bem vindo, "+ nome);

                        tabadmin_create form3 = new tabadmin_create();
                        this.Hide();
                        form3.Show();


                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                finally
                {
                    con.Close();

                }


            }

            else if (comboBox_type.Text == "Aluno")
            {
                SqlConnection con = new SqlConnection("Integrated Security=SSPI;Persist Security Info=False;User ID=DESKTOP-PI7D0K7\\SQLEXPRESS;Initial Catalog=trabalho_tp1_kaio_bruno;Data Source=DESKTOP-PI7D0K7\\SQLEXPRESS");
                SqlCommand cmd = new SqlCommand("select id, nome from participante where login=@login and senha=@senha", con);
                cmd.Parameters.Add("@login", SqlDbType.VarChar).Value = textBox_login.Text;
                cmd.Parameters.Add("@senha", SqlDbType.VarChar).Value = textBox_password.Text;

                try
                {
                    con.Open();
                    SqlDataReader dr = cmd.ExecuteReader();

                    if (dr.HasRows == false)
                    {
                        throw new Exception("Usuario ou senha não encontrado.");
                    }

                        dr.Read();

                        int id;
                        string nome;

                        nome = Convert.ToString(dr["nome"]);
                        id = Convert.ToInt32(dr["id"]);
                        MessageBox.Show("Bem vindo, " + nome);

                        this.Hide();
                        Aluno form = new Aluno();
                        form.id = id;
                        form.Show();
                }

                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                finally
                {
                    con.Close();

                }

            }

        }