c# with mysql dataadapter.fill not doing anything

Question

This should be simple and its just not working. Below code manually creates the datatable and then tries to use adapter.fill method. You can even see commented out code where I manually do an insert of the exact same data, that works just fine. When I use the adapter.fill method, I don't get an error, an exception, anything. It just doesn't work, no data in the table.

            DataTable testdt = new DataTable();
            testdt.Columns.Add("test");
            DataRow testRow = testdt.NewRow();
            testRow[0] = "testing";
            testdt.Rows.Add(testRow);

            MySqlConnection conn = new MySqlConnection(txtDBConnString.Text);
            conn.Open();

            /*MySqlCommand comm = conn.CreateCommand();
            comm.CommandText = "INSERT INTO test(test) VALUES('testing')";
            comm.ExecuteNonQuery();
            conn.Close();*/

            MySqlDataAdapter myadapter = new MySqlDataAdapter();
            myadapter.SelectCommand = new MySqlCommand("select * from test", conn);
            myadapter.Fill(testdt);