title: Creating an excel file with EPPlus, but it is always read-only
body: <p>I'm creating/sending a file with EPPlus like this:</p>
  
  <pre><code>using (ExcelPackage package = new ExcelPackage())
  {
  
      ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Sheet");
      ... //create file here
  
      Response.Clear();
      Response.ContentType = "application/xlsx";
      Response.AddHeader("content-disposition", "attachment; filename=" + filename + ".xlsx");
      Response.BinaryWrite(package.GetAsByteArray());
      Response.End();
  }
  </code></pre>
  
  <p>Everything works fine, except the file always comes back as read-only, and I can't figure out why.  Within the "package" object, there is a file object with a IsReadOnly field, but the file object is null.  I anticipate that I'm not creating the xcel file correctly, but this is the only way I could figure out how to create the file well.  Initially I was using a memory stream, but doing that, I ran into issues when the excel file was bigger than 50 rows.</p>
  
  <p>Edit/update: So I initiate the code block by clicking a button "Download as Excel File".  The code runs, creating the file, and the user is prompted with a "You have chose to open: thisismyexcelfile.xlsx which is a: XLSX file (size here) from: mywebsite.  What should firefox do with this file?"  After selecting "Open with OpenOffice Calc" the spreedsheet opens and displays appropriately but is read-only.</p>
  
  <p>Edit/update: I checked the file properties with OpenOffice.  Under Properties/Security there is a "Open file Read Only" checkbox, but it is already unchecked and disabled.</p>