public sealed class singleton
{
　singleton()
　{}

　public static singleton instance
　{
　　get
　　{
　　　return singletoncreator.instance;
　　}
　}

　class singletoncreator
　{
　　// explicit static constructor to tell c# compiler
　　// not to mark type as beforefieldinit
　　static nested()
　　{}

　　internal static readonly singleton instance = new singleton();
　}
}

public class singletonprovider<t> where t : new()
{
　singletonprovider() { }

　public static t instance
　{
　　get { return singletoncreator.instance; }
　}

　class singletoncreator
　{
　　static singletoncreator() { }
　　internal static readonly t instance = new t();
　}
}

public class testclass
{
　private string _createdtimestamp;

　public testclass ()
　{
　　_createdtimestamp = datetime.now.tostring();
　}

　public void write()
　{
　　debug.writeline(_createdtimestamp);
　}
}

singletonprovider<testclass>.instance.write();