C＃DataGridView无法显示存储在他体内的数据集

Question

我正在尝试将数据从数据库中拉到DataGridView3，您可以在下图的右列中看到它。当我进行调试时，我看到DataSet保持正确的值，并且当我第一次尝试对dataGrid1进行cellClick时它显示正确。但是在随后的尝试中，尽管在调试中DataSet中有正确的值，但DataGridView3不会显示DataSet。 DataGridView3仅显示表的标题，而不显示数据库中的记录。另外，当我单击此标题（从而对行进行排序）时，也会出现记录。您可以在图片2上看到它。因此问题出在 DataGridView 中，它无法显示存储在他中的数据。我尝试在DataGridView3上使用Update()，Refresh()，Show()方法，但并没有帮助。

using MySql.Data.MySqlClient;
using System;
using System.Data;
using System.Windows.Forms;

namespace Lab3
{
    public partial class Form1 : Form
    {
        private MySqlConnection connection = null;

        private DataSet dataSet = null;
        private DataSet dataSetOld = null;

        private MySqlDataAdapter doctorDataAdapter = null;
        private MySqlDataAdapter patientDataAdapter = null;
        private MySqlDataAdapter appointmentDataAdapter = null;          

        public Form1()
        {
            InitializeComponent();
        }

        public void setConnection(MySqlConnection connection)
        {
            this.connection = connection;
        }

        //creating DataSet
        private DataSet getDataSet()
        {
            if (dataSet == null)
            {
                dataSet = new DataSet();
                dataSet.Tables.Add("Doctor");
                dataSet.Tables.Add("Patient");
                dataSet.Tables.Add("Appointment");
            }
            return dataSet;
        }

        //set connection with database
        public MySqlConnection Connect(string host, int port, string database,
             string username, string password)
        {

            string connStr = "Server=" + host + ";Database=" + database + ";port=" + port + ";User Id=" + username + ";password=" + password;

            MySqlConnection connection = new MySqlConnection(connStr);

            connection.Open();
            return connection;
        }

        public void FillDataGridView1ByDoctors()
        {
            getDataSet().Tables["Doctor"].Clear();
            doctorDataAdapter = new MySqlDataAdapter(
                 "SELECT * FROM Doctor", connection);
            new MySqlCommandBuilder(doctorDataAdapter);
            doctorDataAdapter.Fill(getDataSet(), "Doctor");
            dataGridView1.DataSource = getDataSet().Tables["Doctor"];
            this.dataGridView1.Columns["id_doctor"].Visible = false;

        }

        public void FillDataGridView2ByPatients()
        {
            getDataSet().Tables["Patient"].Clear();
            patientDataAdapter = new MySqlDataAdapter(
                "SELECT * FROM Patient", connection);
            new MySqlCommandBuilder(patientDataAdapter);
            patientDataAdapter.Fill(dataSet, "Patient");
            dataGridView2.DataSource = getDataSet().Tables["Patient"];
            this.dataGridView2.Columns["id_patient"].Visible = false;
            dataGridView2.ClearSelection();
        }

        public void FillDataGridView3ByAppointment(string table, int id)
        {

            getDataSet().Tables["Appointment"].Reset();
            if (table == "Doctor")
            {
                appointmentDataAdapter = new MySqlDataAdapter(
                "SELECT patient.name_patient AS `Имя`, patient.surname_patient, appointment.datetime " +
                "FROM patient, appointment, doctor " +
                "WHERE doctor.id_doctor = appointment.id_doctor AND patient.id_patient = appointment.id_patient AND doctor.id_doctor = " +
                 id, connection);
            }
            else
            {
                appointmentDataAdapter = new MySqlDataAdapter(
                "SELECT doctor.name_doctor, doctor.surname_doctor, doctor.speciality, appointment.datetime " +
                "FROM doctor, appointment, patient " +
                "WHERE patient.id_patient = appointment.id_patient AND doctor.id_doctor = appointment.id_doctor AND patient.id_patient = " +
                 id, connection);
            }
            new MySqlCommandBuilder(appointmentDataAdapter);
            appointmentDataAdapter.Fill(dataSet, "Appointment");
            dataGridView3.DataSource = getDataSet().Tables["Appointment"];

        }

        private void dataGridView1_CellClick(object sender,
             DataGridViewCellEventArgs e)
        {
            int selectedRow = dataGridView1.SelectedCells[0].RowIndex;
            int key = (int)dataGridView1.Rows[selectedRow].Cells[0].Value;
            dataGridView2.ClearSelection();
            FillDataGridView3ByAppointment("Doctor", key);
        }

        private void dataGridView2_CellClick(object sender,
             DataGridViewCellEventArgs e)
        {
            int selectedRow = dataGridView2.SelectedCells[0].RowIndex;
            int key = (int)dataGridView2.Rows[selectedRow].Cells[0].Value;
            dataGridView1.ClearSelection();
            FillDataGridView3ByAppointment("Patient", key);
        }  
    }
}