title: Open Excel file .NET Framework 3.5
body: <p>I wrote a VB .NET program that opens an Excel Workbook to put some values.
  Here is the code that open the file:</p>
  
  <pre><code>OpenFileDialog1.FileName = ""
  OpenFileDialog1.Filter = "Excel files (*.xls)|*.xls"
  OpenFileDialog1.ShowDialog()
  filePath = OpenFileDialog1.FileName
  If System.IO.File.Exists(filePath) Then
    oExcel = CreateObject("Excel.Application")
    oExcel.Visible = True
    oBook = oExcel.Workbooks.Open(filePath)
  End If
  </code></pre>
  
  <p>This worked well until I had to run it on an old computer wich didn't have .NET Framework 4.5 nor 4.0</p>
  
  <p>I then change the Framework target to 3.5 and it gave me this error when running:</p>
  
  <pre><code>An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in Microsoft.VisualBasic.dll
  
  Additional information: Old format or invalid type library. (Exception from HRESULT: 0x80028018 (TYPE_E_INVDATAREAD))
  </code></pre>
  
  <p>I guess the way to open an Excel file is not the same for 3.5 or 4.5 so I don't know how I should do.</p>