class NameValueItem {
  private string _name;
  private string _value;

  public NameValueItem() : this(String.Empty, String.Empty) {}
  public NameValueItem(string name, string value) {
    _name = name;
    _value = value;
  }

  public string Name {
    get { return _name; }
    set { _name = value; }
  }

  public string Value {
    get { return _value; }
    set { _value = value; }
  }

  // *** IMPORTANT! User will see this Value in the ComboBox control.
  public override string ToString() {
    return Value;
  }
}

public class MyForm : System.Windows.Forms.Form {
  private System.Windows.Forms.ComboBox cboProgrammingLang;

  private void InitializeComponent() {
    this.cboProgrammingLang = new System.Windows.Forms.ComboBox();
    cboProgrammingLang.SelectedIndexChanged +=
      new System.EventHandler(this.cboProgrammingLang_SelectedIndexChanged);
    this.Controls.Add(cboProgrammingLang);

    this.Load += new System.EventHandler(this.MainForm_Load);
  }

  private void MainForm_Load(object sender, System.EventArgs e) {
    ArrayList al = new ArrayList();

    al.Add(new NameValueItem("1", "Visual Basic"));
    al.Add(new NameValueItem("2", "Visual C#"));
    al.Add(new NameValueItem("3", "Visual FoxPro"));
    
    // *** That's enough. The DisplayMember and ValueMember are unnecessary.
    this.cboProgrammingLang.DataSource = al;
  }

  private void cboProgrammingLang_SelectedIndexChanged(object sender, System.EventArgs e) {
    if (this.cboProgrammingLang.SelectedIndex > -1) {
      NameValueItem item = this.cboProgrammingLang.SelectedValue as NameValueItem;
      MessageBox.Show(
        String.Format("Name: {0}; Value: {1}", item.Name, item.Value));
    }
  }
}