title: How to use Microsoft.Office.Interop.Excel on a machine without installed MS Office?
body: <p>I'm writing an application which works with excel files.
  I need a feature to delete a sheet.
  I have to use an assembly Microsoft.Office.Interop.Excel.dll.</p>
  
  <p>It's running fine on developer machine but when I try to deploy it on server I'm getting an error:</p>
  
  <blockquote>
    <p>Could not load file or assembly 'office, Version=14.0.0.0,
    Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its
    dependencies</p>
  </blockquote>
  
  <p>I understand that problem occurs when MS Office is not installed on a machine.
  Customer don't want to install and buy MS Office on a server not at any price.</p>
  
  <p>I install "Redistributable Primary Interop Assemblies" on developer machine as advised here: <a href="http://forums.asp.net/t/1530230.aspx/1" rel="noreferrer">http://forums.asp.net/t/1530230.aspx/1</a>
  and compile my project again.</p>
  
  <p>Code sample:</p>
  
  <pre><code>public bool DeleteSheet(string tableName)
  {
      Excel.Application app = null;
      Excel.Workbooks wbks = null;
      Excel._Workbook _wbk = null;
      Excel.Sheets shs = null;
  
      bool found = false;
  
      try
      {
          app = new Excel.Application();
          app.Visible = false;
          app.DisplayAlerts = false;
          app.AlertBeforeOverwriting = false;
  
          wbks = app.Workbooks;
          _wbk = wbks.Add(xlsfile);
          shs = _wbk.Sheets;
          int nSheets = shs.Count;
  
          for (int i = 1; i &lt;= nSheets; i++)
          {
              Excel._Worksheet _iSheet = (Excel._Worksheet)shs.get_Item(i);
              if (_iSheet.Name == tableName)
              {
                  _iSheet.Delete();
                  found = true;
  
                  Marshal.ReleaseComObject(_iSheet);
                  break;
              }
              Marshal.ReleaseComObject(_iSheet);
          }
  
          if (!found)
              throw new Exception(string.Format("Table \"{0}\" was't found", tableName));
  
          _wbk.SaveAs(connect, _wbk.FileFormat, Missing.Value, Missing.Value, Missing.Value,
          Missing.Value, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange,
          Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value);
      }
      finally
      {
          _wbk.Close(null, null, null);
          wbks.Close();
          app.Quit();
  
          Marshal.ReleaseComObject(shs);
          Marshal.ReleaseComObject(_wbk);
          Marshal.ReleaseComObject(wbks);
          Marshal.ReleaseComObject(app);
      }
      return true;
  }
  </code></pre>
  
  <p>An exception</p>
  
  <blockquote>
    <p>Retrieving the COM class factory for component with CLSID
    {00024500-0000-0000-C000-000000000046} failed due to the following
    error: 80040154 Class not registered (Exception from HRESULT:
    0x80040154 (REGDB_E_CLASSNOTREG)).</p>
  </blockquote>
  
  <p>occurs on the line </p>
  
  <pre><code>app = new Excel.Application();
  </code></pre>
  
  <p>Can anyone advise on how to get this feature working successfully?</p>