Custom drop-down combo box in C#

combo-box.cs

dbEntities je = new dbEntities();

List<DataDTO> ds = new List<DataDTO>();
foreach (var p in je.purposes)
{
	DataDTO d = new DataDTO();
	d.id = p.purpose_id;
	d.name = p.purpose_code;
	ds.Add(d);
}

// assign array
comboBox1.Items.Clear();
comboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
comboBox1.DataSource = new BindingSource(DataDTO[] d, null);
comboBox1.DisplayMember = "name";
comboBox1.ValueMember = "id";

DataDTO-Combobox.cs

public class DataDTO
{
	public string id { get; set; }
	public string name { get; set; }
}

SelectedIndexChanged-Combobox.cs

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
	DataDTO d = (DataDTO)comboBox1.SelectedItem;
	MessageBox.Show(d.id);
}