C#

parent.Controls.Add(child);

numericUpDown1.KeyDown += new KeyEventHandler(ValidateNumber);
numericUpDown2.KeyDown += new KeyEventHandler(ValidateNumber);
//...
private void ValidateNumber(object sender, KeyEventArgs e)
{
  NumericUpDown nud = sender as NumericUpDown;
  if (nud != null)
  {
    // Should take the other formatting properties into account,
    // but this is only an example.
    int value = int.Parse(nud.Text);
    if (value < nud.Minimum || value > nud.Maximum)
      e.Handled = true;
  }
}

private void UpDownValidating(object sender, System.ComponentModel.CancelEventArgs e)
{
    NumericUpDown nud = sender as NumericUpDown;

    if(nud != null)
    {			
	if(nud.Value < nud.Minimum)
	   nud.Value = nud.Minimum;
   
        if(nud.Value > nud.Maximum)
	   nud.Value = nud.Maximum;
    }
}

//  type-safe price collection
//  we implement ICollection and IEnumerable to have some good functionality
public class PriceCollection : ICollection, IEnumerable
{
   private ArrayList  _prices = new ArrayList();

   //  this is the INDEXER to the contained prices.  Decimal is a good Type for
   //  holding monetary values.
   public Decimal   this[int index]
   {
      get  {  return (Decimal)_prices[index];  }
      put  {  _prices[index] = value;  }
   }

   public int   Count   {  get   {   return _prices.Count;   }   }

   public bool  IsFixedSize   {   get   {   return _prices.IsFixedSize;   }   }

   public bool  IsReadOnly   {  get  {  return _prices.IsReadOnly;   }   }

   public bool  IsSynchronized   {   get   {   return _prices.IsSynchronized;   }   }

   public object   SyncRoot   {   get   {   return _prices.SyncRoot;   }   }

   public void   CopyTo(Array array, int index)
   {
      _prices.CopyTo(array, index);
   }

   public IEnumerator   GetEnumerator()   {   return _prices.GetEnumerator();   }

   public int   Add(Decimal price)
   {
      return _prices.Add(price);
   }

   public void   Remove(int index)
   {
      _prices.RemoveAt(index);
   }
}

public class   MyObjectWithPrices
{
   //   ...

   private PriceCollection   _prices = new PriceCollection();

   //   ...

   //   Aha!
   public PriceCollection   Prices   {  get   {   return _prices;   }   }


   //   ...
}

Decimal  price = myInstance.Prices[4];   //   gets the price at index 4

//   dump prices
foreach (Decimal price in myInstance.Prices)
{
   Console.WriteLine(price.ToString("C"));   //   print as currency
}

//   dump prices another way
for (int i = 0; i < myInstance.Prices.Count; i++)
{
   Console.WriteLine("{0} = {1}", i,
      ((Decimal)myInstance.Prices[i]).ToString("C"));   //   print as currency
}