C#

private void Comunal_KeyDownHandler(object sender, System.Windows.Forms.KeyEventArgs e)
{
   if (e.KeyCode == Keys.Enter)
   {
       e.Handled = true;
       // true means go forwards
       this.GetNextControl((Control)sender, true).Focus();
   }
}

public List<string> CleanupText(List<string> inputLines)
    {
    List<string> outputLines = new List<string>();
    foreach (string s in inputLines)
        {
        // Note: the Trim() and Replace() ensure that (a) there are no false hits and (b) no false misses, respectively
        if (s.Trim().Replace('\t', ' ').Contains(" "))
            outputLines.Add(s);
        else
            outputLines.Add(string.Concat(s, " 0"));
        }
    return outputLines;
    }

public void DoFormStuff(ClassA ca)
    {
    using (MyForm frm = new MyForm())
        {
        frm.ClassA = ca;
        frm.ShowDialog(this);
        }
    }

namespace BallStateExample 
	{
	enum State {Flashing, Played, NotPlayed}
	delegate void BallStateChanged(BallStateChangedEventArgs e);
	
	class BallStateChangedEventArgs
		{
		public int BallIndex { get; set; }
		public State NewState { get; set; }
		}

		
	class Balls
		{
		private readonly State[] _balls;
		
		public Balls(int numBalls)
			{
			_balls = new State[numBalls];
			}
			
		public event BallStateChanged BallStateChanged;

		private void OnBallStateChanged(int index, State newState)
			{
			if (BallStateChanged != null)
				BallStateChanged(new BallStateChangedEventArgs { BallIndex = index, NewState = newState });
			}
			
		public State this[int index]
			{
			get { return _balls[index]; }
			set
				{
				_balls[index] = value;
				OnBallStateChanged(index, value);
				}
			}
		}
		
		
	class BallUser
		{
		private const int NUM_BALLS = 42;
		
		public BallUser()
			{
			Balls = new Balls(NUM_BALLS);
			Balls.BallStateChanged += Balls_StateChanged;
			}
			
		private void Balls_StateChanged(BallStateChangedEventArgs e)
			{
			// Take action in response to a ball state change
			}

		// ...

		// Auto-property (so no backing store need be declared)
		// Private set accessor to prevent consumers of BallUser from
 		// assigning to the property (an action reserved for the constructor of BallUser).
		public Balls Balls { get; private set; }

		// ...
		}
	}