How to get data out of an Arraylist

So in a previous quesiton I asked how i could merge multiple array list into one array list.

This answer worked (also listed below). However, I am having issues getting th开发者_Python百科e records out. How do I get the data out of this multi dimensional arraylist. For example, what if I wanted to get just address out?

ArrayList Names = new ArrayList(); 
ArrayList Phone = new ArrayList(); 
ArrayList Address = new ArrayList(); 
ArrayList res = new ArrayList();  
for(int i=0; i<Names.Count; i++) 
{   
  res.Add(new string[]{Names[i].ToString(), Phone[i].ToString(), Address[i].ToString()}); 
} 

You could do something like the following ... I want to make sure and I note that you might want to come up with better data structures or container classes if you can.

string someAddress = ((string[])res[0])[2];

In this instance we are taking the object (string array) at the first index of res and then indexing into the string array where the address was stored.

You could consider a something like the following though to contain your data with a typed list..

public class Person
{
    public string Name { get; set; }
    public string Phone { get; set; }
    public string Address { get; set; }
}

...

List<Person> people = new List<Person>();
people.Add(new Person() { Name = "Not Me", Phone = "(555) 212-1234", Address = "123 Fake St." });

string address = people[0].Address;

Personally, I would make this a struct.

public struct Record
{
  public String Name;
  public String Telephone;
  public String Address;
}

And push the information in to the structs and then re-reference them. Something like:

ArrayList records = new ArrayList();
for (...) {
  records.Add(new Record(){
    Name = Names[i].ToString(),
    Telephone = Phone[i].ToString(),
    Address = Address[i].ToString()
  });
}
...
Console.WriteLine(records[0].Address);

Assuming this is .NET 2.0 and not anything later so you have to stick with ArrayList, I would just introduce a new class to hold your information.

public class Person
{
    private string _name;
    public string Name { get { return _name; } }
    public Person(string name, string phone, string adress)
    {
        _name = name;
        ...
    }
}

Then you can populate instances of this class in your arraylist and access its properties.

Can I ask why you are creating array lists like you are? In my opinion, you're better off to create a custom object that has 3 properties -> Name, Phone and Address, and simply create a list of those objects:

Resident class:

public class Resident
{
  public string Name { get; set; }
  public string Phone { get; set; }
  public string Address { get; set; }
}

Code:

List<Resident> residents = new List<Resident>();
// populate list

foreach (var res in residents)
  Console.WriteLine(res.Address);