String GetFileExtension(String FileNameWithoutExtension);

SR>String GetFileExtension(String FileNameWithoutExtension);
SR>

        /// <summary>
        /// Enumerates the flags for the FindMimeFromData function
        /// </summary>
        [Flags]
        public enum MimeFlags
        {
            /// <summary>
            /// No flags specified
            /// </summary>
            None = 0
        };

        [DllImport("urlmon.dll", CharSet = CharSet.Auto)]
        private static extern int FindMimeFromData(IntPtr pBC, string url, byte[] buffer, int bufferSize,
            string pwzMimeProposed, MimeFlags mimeFlags, out string ppwzMimeOut, int dwReserved);
        /// <summary>
        /// Determines the Multipurpose Internet Mail Extensions (MIME) type from the data provided.
        /// </summary>
        /// <param name="url">String value that contains the URL of the data. This can be set to null if buffer contains the data to be sniffed.</param>
        /// <param name="buffer">Buffer containing the data to be sniffed. This can be set to null if url contains a valid URL.</param>
        /// <param name="mimeProposed">String value containing the proposed MIME type. This can be set to null.</param>
        /// <returns>String value containing the suggested MIME type</returns>
        public static string FindMimeFromData(string url, byte[] buffer, string mimeProposed)
        {
            const int maxLen = 255;
            string result;
            int hr;
            int bufLen = 0;
            if (buffer != null)
                bufLen = buffer.Length < maxLen ? buffer.Length : maxLen;
            hr = FindMimeFromData(new IntPtr(0), url, buffer, bufLen, mimeProposed, MimeFlags.None, out result, 0);
            return result;
        }

        uint pcchOut = 0;
    AssocQueryString(AssocF.Open_ByExeName, AssocStr.Executable, doctype, null, null, ref pcchOut);
    StringBuilder pszOut = new StringBuilder((int)pcchOut);
    AssocQueryString(AssocF.Open_ByExeName, AssocStr.Executable, doctype, null, pszOut, ref pcchOut);

1.2.0 alpha rev. 655