Выборка в datagridview с переменной

        private void InitCommandCollection() {
            Form1 frm1 = new Form1();
            string tcep = frm1.textBox4.Text;
            this._commandCollection = new global::Devart.Data.MySql.MySqlCommand[1];
            this._commandCollection[0] = new global::Devart.Data.MySql.MySqlCommand();
            this._commandCollection[0].Connection = this.Connection;
            this._commandCollection[0].CommandText = "SELECT id_opory, marka, photo, strana, kolvo_tcep FROM mydb.opory WHERE kolvo_tcep='"+tcep+"'";
            this._commandCollection[0].CommandType = global::System.Data.CommandType.Text;
        }

    static class Values
    {
        public static string Value{ get; set; }
    }

        void buttonClick(object sender, EventArgs e)
        {
            Values.Value= textBox1.Text;
                Form2 frm = new Form2();
            frm.ShowDialog();
        }

public Form2()
        {
            InitializeComponent();
                        textBox1.Text = Values.Value;
        }

        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
 
        }

            string connectString = "user id=newuser;password=mysql2018;host=localhost;database=mydb;unicode=True;persist security info=True";
 
            Devart.Data.MySql.MySqlConnection myConnection = new Devart.Data.MySql.MySqlConnection(connectString);
 
            myConnection.Open();
 
            string query = "SELECT marka FROM mydb.opory WHERE kolvo_tcep='" + textBox19.Text + "'";
 
            Devart.Data.MySql.MySqlCommand command = new Devart.Data.MySql.MySqlCommand(query, myConnection);
 
            Devart.Data.MySql.MySqlDataReader reader = command.ExecuteReader();
 
            List<string[]> data = new List<string[]>();
 
            while (reader.Read())
            {
                data.Add(new string[1]);
 
                data[data.Count - 1][0] = reader[0].ToString();
            }
 
            reader.Close();
 
            myConnection.Close();
 
            foreach (string[] s in data)
                dataGridView1.Rows.Add(s);