hello, I'm trying to add column to datagridview2 automatically help plz :(

private void button3_Click(object sender, EventArgs e)
        {
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
                {
                    string nn = dataGridView1.Rows[i].Cells["matricule"].Value.ToString();
                    db_connection();


                    MySqlCommand cmd = new MySqlCommand();
                    string query = "SELECT mat,dnd FROM test where mat='" + nn + "'";

                    cmd.Connection = connect;

                    DataSet ds = new DataSet();
                        
                      using (MySqlDataAdapter adapter = new MySqlDataAdapter(query, conn))
                        {
                        
                          while(adapter != null){
                              adapter.Fill(ds);


                              if (ds.Tables[0].Rows.Count != 0)
                              {

                                  DataGridViewColumn col = new DataGridViewTextBoxColumn();
                                  col.HeaderText = ds.Tables[0].ToString();
                                  int colIndex = dataGridView2.Columns.Add(col);

                                //dataGridView2.DataSource = ds.Tables[0];

                              }
                          }
                        }
                    

                }
                int count = dataGridView2.Rows.Count;
                label6.Text = count.ToString();         
        }
    }