FormatUtil.cs

    public static class FormatUtil
    {
        public static CustomDateFormat CustomFormat(this DateTime dateTime)
        {
            return new CustomDateFormat(dateTime);
        }
    }

    public class CustomDateFormat
    {
        private DateTime _value;
        public CustomDateFormat(DateTime value)
        {
            _value = value;
        }
        public string ToLongDateString()
        {
            return _value.ToString("MMMM dd, yyyy");
        }
    }