AerolineaFrba.Compra.Form6.button1_Click C# (CSharp) Method

        private void button1_Click(object sender, EventArgs e)
        {
            if (!validarDNIYApellido())
            {

                button2.Enabled = true;
                txtDire.Enabled = true;
                dp.Enabled = true;
                txtNom.Enabled = true;
                txtTel.Enabled = true;
                txtMail.Enabled = true;

                SqlDataReader reader;
                SqlCommand command = new SqlCommand();
                command.CommandType = CommandType.Text;
                command.CommandText = "select * from [ABSTRACCIONX4].buscarCliente(@dni,@ape)";
                command.Connection = Program.conexion();

                command.Parameters.AddWithValue("@dni", txtDni.Text);
                command.Parameters.AddWithValue("@ape", txtApe.Text);

                reader = command.ExecuteReader();

                reader.Read();

                if (reader.HasRows)
                {
                    encontroCliente = true;

                    clienteCodigo = (int)reader.GetValue(0);
                    txtNom.Text = reader.GetValue(2).ToString();
                    txtDire.Text = reader.GetValue(4).ToString();
                    txtTel.Text = reader.GetValue(5).ToString();
                    txtMail.Text = reader.GetValue(6).ToString();
                    dp.Value = (DateTime)reader.GetValue(7);
                    txtDni.Enabled = false;

                }
                else
                {
                    SqlDataReader varCli = this.tieneDocumento(txtDni.Text);

                    varCli.Read();

                    if (varCli.HasRows)
                    {
                        button2.Enabled = false;
                        txtDire.Enabled = false;
                        dp.Enabled = false;
                        txtNom.Enabled = false;
                        txtTel.Enabled = false;
                        txtMail.Enabled = false;

                        MessageBox.Show("Dni inválido. Ya existe un Cliente con ese DNI", "Error cliente", MessageBoxButtons.OK);
                    }
                    else
                    {
                        MessageBox.Show("No se encuentra cargado el cliente en la BD. Por favor, ingresar los datos para darle de alta", "Cliente no encontrado", MessageBoxButtons.OK);
                    }
                }
            }
        }