how-to write Singleton class in C# , asp.net

A great post about rounding corners applicable for dynamic controls
using System.Collections.Generic;


namespace BL
{
//hop_conf
public class Conf
{

#region Singleton Instantiation
Conf () { RegisterVariables (); }
public static Conf Instance
{
get { return Singleton.instance; }
}
class Singleton
{
static Singleton () { }
internal static readonly Conf instance =
new Conf ();
}
#endregion
private IDictionary _innerHash = new Dictionary ();
public IDictionary Vars
{
get { return _innerHash; }
}


private void RegisterVariables ()
{
_innerHash.Add ( "varName" , "theVarName" );
_innerHash.Add ( "appName" , "theAppName" );
_innerHash.Add ( "appNameLong" , "theAppNameLong" );

} //eof method RegisterVariables



} //eof class Conf

} //eof namespace

//how-to access conf variables BL.Conf.Instance.Vars [ "varName" ] would give you "theVarName