Multithreaded File/Folder Finder

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

namespace FileFind
{
    /// <summary>
    /// Represents a wildcard running on the
    /// <see cref="System.Text.RegularExpressions"/> engine.
    /// /// Credit for this class belongs to reinux as published in the
    /// "Converting Wildcards to Regexes" article at http://www.codeproject.com/KB/recipes/wildcardtoregex.aspx
    /// </summary>
    /// 
    
        public class Wildcard : Regex
    {
        /// <summary>
        /// Initializes a wildcard with the given search pattern.
        /// </summary>
        /// <param name="pattern">The wildcard pattern to match.</param>
        public Wildcard(string pattern)
            : base(WildcardToRegex(pattern))
        { }

        /// <summary>
        /// Initializes a wildcard with the given search pattern and options.
        /// </summary>
        /// <param name="pattern">The wildcard pattern to match.</param>
        /// <param name="options">A combination of one or more
        /// <see cref="System.Text.RegexOptions"/>.</param>
        public Wildcard(string pattern, RegexOptions options)
            : base(WildcardToRegex(pattern), options)
        { }

        /// <summary>
        /// Converts a wildcard to a regex.
        /// </summary>
        /// <param name="pattern">The wildcard pattern to convert.</param>
        /// <returns>A regex equivalent of the given wildcard.</returns>
        public static string WildcardToRegex(string wildcard)
        {
            StringBuilder sb = new StringBuilder(wildcard.Length + 8);
            sb.Append("^");
            for (int i = 0; i < wildcard.Length; i++)
            {
                char c = wildcard[i]; switch (c)
                {
                    case '*':
                        sb.Append(".*"); break;
                    case '?':
                        sb.Append("."); break;
                    case '\\':
                        if (i < wildcard.Length - 1)
                            sb.Append(Regex.Escape(wildcard[++i].ToString()));
                        break;
                    default:
                        sb.Append(Regex.Escape(wildcard[i].ToString()));
                        break;
                }
            }
            sb.Append("$");
            return sb.ToString();
        } //ends public static string WildcardToRegex(...
    }
}