title: C# create/modify/read .xlsx files
body: <p>I am looking for a way to create, modify, read .xlsx files in C# without installing Excel or creating files on the server before giving to the user to download.</p>
  
  <p>I found NPOI <a href="http://npoi.codeplex.com/" rel="noreferrer">http://npoi.codeplex.com/</a> which looks great but supports .xls not .xlsx</p>
  
  <p>I found ExcelPackage <a href="http://excelpackage.codeplex.com/" rel="noreferrer">http://excelpackage.codeplex.com/</a> which looks great but has the additional overhead of creating the file on the server before it can be sent to the user.
  Does anyone know of a way around this?</p>
  
  <p>I found EPPlus <a href="http://epplus.codeplex.com" rel="noreferrer">http://epplus.codeplex.com</a> but I am not not certain if this requires creation of a file on the server before it can be sent to the user?</p>
  
  <p>I am pretty new to this so any guidance/examples etc., would be very much appreciated.</p>