C#

    public ComboBox cbState;
    public ComboBox cbCities;
    public static int NumberOfPeople = 1;
 

    private void btnAddNewPerson_Click(object sender, EventArgs e)
    {
 
        NumberOfPeople++;
 
        TextBox txtPerson = new TextBox();
        txtPerson.Name = "Person" + NumberOfPeople;
        Panel.Controls.Add(txtPerson);
 
        //  ADD State ComboBox
        cbState = new ComboBox();
        cbState.Name = "State" + NumberOfPeople;
        cbState.Enabled = true;
        cbState.DropDownStyle = ComboBoxStyle.DropDownList;
        Panel.Controls.Add(cbState);
 
        //  ADD City ComboBox
        cbCity = new ComboBox();
        cbCity.Name = "City" + NumberOfPeople;
        cbCity.DropDownStyle = ComboBoxStyle.DropDownList;
        cbCity.Enabled = false;
        cbCity.SelectedValueChanged += new System.EventHandler(this.ChangeState);
        Panel.Controls.Add(cbCity);
 
    }
 
    private void ChangeState(object sender, EventArgs e)
    {
 
       ..... Don't know how to properly identify the dynamically created City ComboBox that is in the same row as the State ComboBox that was just changed, and manipulate/populate it.....
 
    }

• Maintain a list of data objects, containing the data you want:
  

  class Person : BaseNotifier {
   private string name;
   public string Name { get { return name; } set { name = value; Notify('Name'); } }
   private string state;
   public string State { get { return state; } set { state = value; Notify('State'); } }
  }

  (BaseNotifier is a simple implementation of INotifyPropertyChanged, see end of post), and in your main class:
   
  

  List<Person> people = new List<Person>();

 

• Create a custom control that can be bound to a person:
  

  class PersonPanel : Panel, INotifyPropertyChanged {
   TextBox nameTextBox;
   ComboBox stateCombo;
   // for the sake of example, probably would be held elsewhere or loaded from database
   public static readonly string[] States = { "NSW", "SA", "WA", "NT", "ACT", "TAS" };
   
   public PersonPanel(){
    Width = 200;
    Height = 30;
    Controls.Add(nameTextBox = new TextBox());
    nameTextBox.Left = nameTextBox.Top = 5;
    // ... etc
  
    nameTextBox.TextChanged += (s, e) => Notify("Name");
    stateCombo.SelectedIndexChanged += (s, e) => Notify("State");
   }
   
   public string Name {
    get { return nameTextBox.Text; }
    set { nameTextBox.Text = value; }
   }
    
   public string State {
    get { return (string)stateCombo.SelectedItem; }
    set { stateCombo.SelectedItem = value; }
   }
   
   public event PropertyChangedEventHandler PropertyChanged;
   
   private void Notify(string property){
    PropertyChangedEventHandler h = PropertyChanged;
    if(null != h) h(this, new PropertyChangedEventArgs(property));
   }
  }

  The notification is so two way data binding can work.
   
  
• When you add a new person, create and bind one of these to a new Person object
  

  void AddNewPerson(){
   Person person = new Person();
   if(people.Count > 0) person.State = people[people.Count - 1].State;
   people.Add(person);
   
   PersonPanel panel = new PersonPanel();
   panel.DataBindings.Add("Name", person, "Name");
   panel.DataBindings.Add("State", person, "State");
   Panel.Controls.Add(panel);
  }

public abstract class BaseNotifier : INotifyPropertyChanged {
 public event PropertyChangedEventHandler PropertyChanged;
 
 protected void Notify(string property){
  PropertyChangedEventHandler h = PropertyChanged;
  if(null != h) h(this, new PropertyChangedEventArgs(property));
 }
}

class FooAttribute : MyAttribute
{
  public FooAttribute() : base ( foo ) {}
}
 
class BarAttribute : MyAttribute
{
  public BarAttribute() : base ( bar ) {}
}