/// <summary>
        /// Extracts from the xslx file the part specified with partMarker
        /// </summary>
        /// <param name="partMarker"></param>
        /// <returns></returns>
        private XElement GetXLSXPart(string partMarker)
        {
            UnZipper unzip;
            Stream   s = theFile.OpenRead();

            unzip = new UnZipper(s);
            XElement partElement = null;

            foreach (string filename in unzip.GetFileNamesInZip())
            {
                Stream partStream = unzip.GetFileStream(filename);
                if (filename == partMarker)
                {
                    partElement = XElement.Load(XmlReader.Create(partStream));
                    partStream.Close();
                    return(partElement);
                }
            }
            return(null);
        }
		/// <summary>
		/// Extracts from the xslx file the part specified with partMarker
		/// </summary>
		/// <param name="partMarker"></param>
		/// <returns></returns>
		private XElement GetXLSXPart(string partMarker)
		{
			UnZipper unzip;
			Stream s = theFile.OpenRead();
			unzip = new UnZipper(s);
			XElement partElement = null;

			foreach (string filename in unzip.GetFileNamesInZip())
			{
				Stream partStream = unzip.GetFileStream(filename);
				if (filename == partMarker)
				{
					partElement = XElement.Load(XmlReader.Create(partStream));
					partStream.Close();
					return partElement;
				}
			}
			return null;
		}