title: VSTO Excel Read from Current Open Workbook
body: <p>Is it possible to read from an open Excel (xlsx) using EPPlus? I want the user to be able to open an Excel document, click the Add-In button and read data from the active worksheet. I don't need to write to the worksheet, only read from it. </p>
  
  <p>Using interop I was able to get the full path to the open workbook but when I tried to actually access the workbook I got an I/O error. Any ideas how to get around this? </p>
  
  <pre><code>    var test = ( Microsoft.Office.Interop.Excel.Workbook ) Globals.ThisAddIn.Application.ActiveWorkbook;
      var test2 = test.ActiveSheet;
      //var test21 = ( Microsoft.Office.Interop.Excel.Workbook ) Globals.ThisAddIn.Application.ActiveSheet;
      var test3 = new FileInfo( test.FullName );
  
  
      using ( ExcelPackage package = new ExcelPackage( test3) ) // &lt;--- I/O error here
      {
          var worksheet = package.Workbook.Worksheets[ "Sheet1" ]; 
          string myString = String.Format( "{0}", worksheet.Cells[ 1, 1 ].Text );
      }
  </code></pre>