C#

Key     Hashcode Bag
tommy   23    -> 3
frang   43    -> 3
fratiti 12    -> 2
tom     45    -> 0
eddtom  23    -> 3
frankie 67    -> 2
blue    56    -> 1

bag #0: (tom;object)
bag #1: (blue;object)
bag #2: (fratiti;object)
bag #3: (tommy;object) (frang;object) (eddtom;object)
bag #4: 

ArrayList keys   = new ArrayList();
ArrayList values = new ArrayList();

public void Insert(string key, object value)
{
  int index = keys.BinarySearch(key);
  if (index >= 0) // key already in the keys list
  {
    values[index] = value;
  }
  else
  {
    keys.Insert(~index, key);
    values.Insert(~index, value);
  }
}

public struct Range { public int From; public To };

public Range Find(string keyStart)
{
  Range range;
  range.From = keys.BinarySearch(keyStart);
  range.To   = keys.BinarySearch(keyStart + char.MaxValue);
  if (range.From < 0) range.From = ~range.From;
  if (range.To < 0) range.To = ~range.To - 1;
  return range;
}

[ROOT]
 |- b
 |  '-----------------> (blue;object)
 |- e
 |  '-----------------> (eddtom;object)
 |- f
 |  '-r
 |    '-a
 |      |-n
 |      | |-g
 |      | | '---------> (frang;object)
 |      | '-k
 |      |   '---------> (frankie;object)
 |      '-t
 |        '-----------> (fratiti;object)
 '- t
    '-o
      '-m
        |-------------> (tom;object)
        '-m
          '-----------> (tommy;object)

Regex re = new Regex("\d{3}-?\d{2}-?\d-?\d{3}$");

if(!re.IsMatch(txtAccount.Text))
{
    // Display error and so on
    e.Cancel = true;
}

class DBController
{
    static DBController()
    {
        conn = new SqlConnection(....);
    }
 
    public static Customer GetCustomer(int id)
    {
        conn.Open();

        SqlCommand cmd = new SqlCommand("...", conn);
        SqlDataReader rdr = cmd.ExecuteReader();
        rdr.Read();
 
        Customer customer = new Customer()
        customer.Name = (string) rdr["Name"];

        rdr.Close();
        conn.Close();
 
        return customer;
    }

    private static SqlConnection conn;
}

try<br />
{<br />
 Form2 f2 = new Form2();<br />
 f2.ShowDialog();<br />
}<br />
catch (Exception ex)<br />
{<br />
 MessageBox.Show("Exception caught in button1_Click()\n"+ex.ToString());<br />
}