public class SingletonClassName:IEnumerable<string>
    {
        private static volatile SingletonClassName Object1 = null;
        private static object SynRoot = new object();
               

        private SingletonClassName()
        {
            // do nothing
        }

        public static SingletonClassName GetInstance()
        {
            SingletonClassName RetVal = null;

            // check SingletonClass object is null or not. If it is null then create Object
            if (SingletonClassName.Object1 == null)
            {
                // lock code block to avoid dead lock condition and it is required in multi-threaded environment
                lock (SingletonClassName.SynRoot)
                {
                    // initialize object
                    SingletonClassName.Object1 = new SingletonClassName();
                }
            }

            // return Singleton class object
            RetVal = SingletonClassName.Object1;
           

            return RetVal;
        }
    }