C#

using System;
using System.Collections;
using System.Text.RegularExpressions;

public class Test
{		
	private int GetFormatItemCount(string s)
	{
		ArrayList al = new ArrayList();
		Regex r = new Regex("{*[0-9]*}");
		Match m = r.Match(s);
		while(m.Success)
		{
			if(!al.Contains(m.Value))
				al.Add(m.Value);
			m = m.NextMatch();
		}
		return al.Count;
	}

	[STAThread]		
	static void Main()		
	{            
		Test t = new Test();
		string arg = "This {0} is a {1} and {2} and {0} for good measure.";
		int count = t.GetFormatItemCount(arg);
		Console.WriteLine(count + " items in string.");
		Console.Read();		
	}	
}

StreamReader reader = new StreamReader(networkStream, Encoding.UTF8);
StreamWriter writer = new StreamWriter(networkStream, Encoding.UTF8);

<br />
panelContainer.Hide();<br />
//do the changes, display new data etc.<br />
panelContainer.Show();<br />

...
bool IgnoreChangeEvent = false;
...
if (condition)
{
    IgnoreChangeEvent=true;
    box.SelectedIndex = -1;
}
 ...
box.SelectedIndex_Changed(object sender, EventArgs e)
{
  if (IgnoreChangeEvent)
   {
     IgnoreChangeEvent=false;
      return;
   }
  ... determine if action is needed
 }