/// <summary>
        /// Deallocates the files in a message.
        /// </summary>
        /// <param name="message">The message to deallocate the files from.</param>
        private static void DeallocFiles(NativeMethods.MapiMessage message)
        {
            if (message.Files == IntPtr.Zero)
            {
                return;
            }

            Type fileDescType = typeof(NativeMethods.MapiFileDescriptor);
            int  fsize        = Marshal.SizeOf(fileDescType);

            // Get the ptr to the files
            int runptr = (int)message.Files;

            // Release each file
            for (int i = 0; i < message.FileCount; i++)
            {
                Marshal.DestroyStructure((IntPtr)runptr, fileDescType);
                runptr += fsize;
            }
            // Release the file
            Marshal.FreeHGlobal(message.Files);
        }
        /// <summary>
        /// Sends the mail message.
        /// </summary>
        private void ShowMail()
        {
            NativeMethods.MapiMessage message = new NativeMethods.MapiMessage();

            using (RecipientCollection.InteropRecipientCollection interopRecipients
                       = _recipientCollection.GetInteropRepresentation()) {
                message.Subject  = _subject;
                message.NoteText = _body;

                message.Recipients     = interopRecipients.Handle;
                message.RecipientCount = _recipientCollection.Count;

                // Check if we need to add attachments
                if (_files.Count > 0)
                {
                    // Add attachments
                    message.Files = AllocAttachments(out message.FileCount);
                }

                // Signal the creating thread (make the remaining code async)
                _manualResetEvent.Set();

                int error = (int)NativeMethods.MAPISendMail(IntPtr.Zero, IntPtr.Zero, message, MAPI_DIALOG, 0);

                if (_files.Count > 0)
                {
                    // Deallocate the files
                    DeallocFiles(message);
                }

                // Check for error
                if (error != SUCCESS_SUCCESS)
                {
                    throw new Exception(LogErrorMapi(error));
                }
            }
        }