private static ICollection <FileInfo> GetLinkSources(Excel.Workbook workbook)
{
List <FileInfo> attachments = new List <FileInfo>();
Array links = (Array)workbook.LinkSources(Excel.XlLink.xlExcelLinks);
if (links != null)
{
foreach (String link in links)
{
FileInfo f = new FileInfo(link);
attachments.Add(f);
}
}
return(attachments);
}