title: ClosedXML return File
body: <p>I'm using blazor and .net 5. I'm trying to do an excel export using ClosedXML. Here is the simple method I wrote:</p>
  <pre><code>public IActionResult CreateExcelSheet()
          {
  
              using (var wbook = new XLWorkbook())
              {
                  var ws = wbook.Worksheets.Add(&quot;Sheet1&quot;);
                  ws.Cell(&quot;A1&quot;).Value = &quot;1&quot;;
  
                  using (var stream = new MemoryStream())
                  {
                      wbook.SaveAs(stream);
                      var content = stream.ToArray();
                      return File(content, &quot;application/vnd.openxmlformats-officedocument.spreadsheetml.sheet&quot;, &quot;Opportunities.xlsx&quot;);
                  }
              }
          }
  </code></pre>
  <p>The return file has a red underline saying Non-invocable member 'File' cannot be used like a method.
  I'm not really sure how to correct this... I'm also not sure if I'm doing this right with blazor and .net 5. Any help is greatly appreciated!</p>